diff --git a/.vscode/settings.json b/.vscode/settings.json
index 977478f..77b3c43 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,5 +1,5 @@
 {
-    "editor.formatOnSave": true,
+    "editor.formatOnSave": false,
     "[php]": {
         "editor.defaultFormatter": "bmewburn.vscode-intelephense-client"
     },
diff --git a/database/factories/ProductFactory.php b/database/factories/ProductFactory.php
index 8d7d1b9..0088b25 100644
--- a/database/factories/ProductFactory.php
+++ b/database/factories/ProductFactory.php
@@ -68,4 +68,25 @@ class ProductFactory extends Factory
     {
         return $this->state(['featured' => true]);
     }
+
+    public function withPrices(int $count = 1): static
+    {
+        return $this->afterCreating(function (Product $product) use ($count) {
+            $prices = \Blax\Shop\Models\ProductPrice::factory()
+                ->count($count)
+                ->create([
+                    'purchasable_type' => get_class($product),
+                    'purchasable_id' => $product->id,
+                    'unit_amount' => $this->faker->randomFloat(2, 10, 1000),
+                    'currency' => 'EUR',
+                ]);
+
+            // Set the first price as default
+            if ($prices->isNotEmpty()) {
+                $defaultPrice = $prices->first();
+                $defaultPrice->is_default = true;
+                $defaultPrice->save();
+            }
+        });
+    }
 }
diff --git a/database/factories/ProductPriceFactory.php b/database/factories/ProductPriceFactory.php
new file mode 100644
index 0000000..c6fa51b
--- /dev/null
+++ b/database/factories/ProductPriceFactory.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Blax\Shop\Database\Factories;
+
+use Blax\Shop\Models\ProductPrice;
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Illuminate\Support\Str;
+
+class ProductPriceFactory extends Factory
+{
+    protected $model = ProductPrice::class;
+
+    public function definition()
+    {
+        return [
+            'unit_amount' => $this->faker->randomFloat(2, 1, 1000),
+            'currency' => 'EUR',
+            'is_default' => false,
+        ];
+    }
+}
diff --git a/database/migrations/create_blax_shop_tables.php.stub b/database/migrations/create_blax_shop_tables.php.stub
index b9dd936..a5e3e02 100644
--- a/database/migrations/create_blax_shop_tables.php.stub
+++ b/database/migrations/create_blax_shop_tables.php.stub
@@ -116,13 +116,13 @@ return new class extends Migration
         if (!Schema::hasTable(config('shop.tables.product_prices', 'product_prices'))) {
             Schema::create(config('shop.tables.product_prices', 'product_prices'), function (Blueprint $table) {
                 $table->uuid('id')->primary();
-                $table->uuid('product_id');
+                $table->uuidMorphs('purchasable');
                 $table->string('stripe_price_id')->nullable();
                 $table->string('name')->nullable();
                 $table->string('type')->default('one_time'); // one_time, recurring
-                $table->string('currency', 3)->default('USD');
-                $table->integer('price')->default(0); // Store as smallest currency unit (cents)
-                $table->integer('sale_price')->nullable();
+                $table->string('currency', 3)->default('EUR');
+                $table->integer('unit_amount')->default(0); // Store as smallest currency unit (cents)
+                $table->integer('sale_unit_amount')->nullable();
                 $table->boolean('is_default')->default(false);
                 $table->boolean('active')->default(true);
                 $table->string('billing_scheme')->nullable(); // per_unit, tiered
@@ -132,10 +132,7 @@ return new class extends Migration
                 $table->json('meta')->nullable();
                 $table->timestamps();
 
-                $table->index(['product_id', 'currency']);
-                $table->index(['product_id', 'is_default']);
-                $table->index(['active', 'type']);
-                $table->foreign('product_id')->references('id')->on(config('shop.tables.products', 'products'))->onDelete('cascade');
+                $table->index('currency');
             });
         }
 
@@ -271,18 +268,17 @@ return new class extends Migration
             Schema::create(config('shop.tables.cart_items', 'cart_items'), function (Blueprint $table) {
                 $table->uuid('id')->primary();
                 $table->uuid('cart_id');
-                $table->uuid('product_id');
+                $table->uuidMorphs('purchasable');
                 $table->integer('quantity')->default(1);
-                $table->decimal('price', 10, 2);
+                $table->decimal('price', 10, 2)->default(0);
                 $table->decimal('regular_price', 10, 2)->nullable();
                 $table->decimal('subtotal', 10, 2);
-                $table->json('attributes')->nullable();
+                $table->json('parameters')->nullable();
                 $table->json('meta')->nullable();
                 $table->timestamps();
 
                 $table->index(['cart_id', 'product_id']);
                 $table->foreign('cart_id')->references('id')->on(config('shop.tables.carts', 'carts'))->onDelete('cascade');
-                $table->foreign('product_id')->references('id')->on(config('shop.tables.products', 'products'))->onDelete('cascade');
             });
         }
 
diff --git a/src/Contracts/Cartable.php b/src/Contracts/Cartable.php
new file mode 100644
index 0000000..57a666c
--- /dev/null
+++ b/src/Contracts/Cartable.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace Blax\Shop\Contracts;
+
+interface Cartable
+{
+}
diff --git a/src/Contracts/Purchasable.php b/src/Contracts/Purchasable.php
index 0ce9c13..04e9e0c 100644
--- a/src/Contracts/Purchasable.php
+++ b/src/Contracts/Purchasable.php
@@ -10,5 +10,7 @@ interface Purchasable
 
     public function decreaseStock(int $quantity = 1): bool;
 
-    public function increaseStock(int $quantity = 1): void;
+    public function increaseStock(int $quantity = 1): bool;
+
+    public function purchases();
 }
diff --git a/src/Exceptions/NotEnoughStockException.php b/src/Exceptions/NotEnoughStockException.php
new file mode 100644
index 0000000..4e79d15
--- /dev/null
+++ b/src/Exceptions/NotEnoughStockException.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace Blax\Shop\Exceptions;
+
+use Exception;
+
+class NotEnoughStockException extends Exception {}
diff --git a/src/Models/Cart.php b/src/Models/Cart.php
index 9ebc45d..bd45a41 100644
--- a/src/Models/Cart.php
+++ b/src/Models/Cart.php
@@ -2,6 +2,7 @@
 
 namespace Blax\Shop\Models;
 
+use Blax\Shop\Contracts\Cartable;
 use Blax\Workkit\Traits\HasExpiration;
 use Illuminate\Database\Eloquent\Concerns\HasUuids;
 use Illuminate\Database\Eloquent\Model;
@@ -109,4 +110,30 @@ class Cart extends Model
             $cart->items()->delete();
         });
     }
+
+    public function addToCart(
+        Model $cartable, 
+        $quantity = 1,
+        $parameters = []
+    ) : CartItem {
+
+        // $cartable must implement Cartable
+        if (! $cartable instanceof Cartable) {
+            throw new \Exception("Item must implement the Cartable interface.");
+        }
+
+        $cartItem = $this->items()->create([
+            'purchasable_id' => $cartable->getKey(),
+            'purchasable_type' => get_class($cartable),
+            'quantity' => $quantity,
+            'price' => ($cartable?->sale_unit_amount ?? $cartable?->unit_amount ?? 0),
+            'regular_price' => $cartable?->unit_amount,
+            'subtotal' => ($cartable?->sale_unit_amount ?? $cartable?->unit_amount ?? 0) * $quantity,
+            'parameters' => $parameters,
+        ]);
+
+        $cartItem = $cartItem->fresh();
+
+        return $cartItem;
+    }
 }
diff --git a/src/Models/CartItem.php b/src/Models/CartItem.php
index 1b37e92..b245a72 100644
--- a/src/Models/CartItem.php
+++ b/src/Models/CartItem.php
@@ -2,22 +2,24 @@
 
 namespace Blax\Shop\Models;
 
+use Blax\Workkit\Traits\HasMeta;
 use Illuminate\Database\Eloquent\Concerns\HasUuids;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 
 class CartItem extends Model
 {
-    use HasUuids;
+    use HasUuids, HasMeta;
 
     protected $fillable = [
         'cart_id',
-        'product_id',
+        'purchasable_id',
+        'purchasable_type',
         'quantity',
         'price',
         'regular_price',
         'subtotal',
-        'attributes',
+        'parameters',
         'meta',
     ];
 
@@ -26,7 +28,7 @@ class CartItem extends Model
         'price' => 'decimal:2',
         'regular_price' => 'decimal:2',
         'subtotal' => 'decimal:2',
-        'attributes' => 'array',
+        'parameters' => 'array',
         'meta' => 'array',
     ];
 
@@ -59,9 +61,18 @@ class CartItem extends Model
         return $this->belongsTo(config('shop.models.cart'), 'cart_id');
     }
 
-    public function product(): BelongsTo
+    public function purchasable()
     {
-        return $this->belongsTo(config('shop.models.product'), 'product_id');
+        return $this->morphTo('purchasable');
+    }
+
+    public function product(): BelongsTo|null
+    {
+        if ($this->purchasable_type === config('shop.models.product', Product::class)) {
+            return $this->belongsTo(config('shop.models.product'), 'purchasable_id');
+        }
+
+        return null;
     }
 
     public function getSubtotal(): float
diff --git a/src/Models/Product.php b/src/Models/Product.php
index 28e14c9..a2400d1 100644
--- a/src/Models/Product.php
+++ b/src/Models/Product.php
@@ -3,19 +3,22 @@
 namespace Blax\Shop\Models;
 
 use App\Services\StripeService;
+use Blax\Shop\Contracts\Cartable;
 use Blax\Workkit\Traits\HasMetaTranslation;
 use Blax\Shop\Events\ProductCreated;
 use Blax\Shop\Events\ProductUpdated;
 use Blax\Shop\Contracts\Purchasable;
+use Blax\Shop\Exceptions\NotEnoughStockException;
 use Illuminate\Database\Eloquent\Concerns\HasUuids;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
 use Illuminate\Database\Eloquent\Relations\HasMany;
+use Illuminate\Database\Eloquent\Relations\MorphMany;
 use Illuminate\Support\Facades\Cache;
 use Illuminate\Support\Facades\DB;
 
-class Product extends Model implements Purchasable
+class Product extends Model implements Purchasable, Cartable
 {
     use HasFactory, HasUuids, HasMetaTranslation;
 
@@ -49,7 +52,6 @@ class Product extends Model implements Purchasable
 
     protected $casts = [
         'manage_stock' => 'boolean',
-        'in_stock' => 'boolean',
         'virtual' => 'boolean',
         'downloadable' => 'boolean',
         'meta' => 'object',
@@ -62,8 +64,6 @@ class Product extends Model implements Purchasable
         'sort_order' => 'integer',
     ];
 
-    // Remove - causes issues with casting
-
     protected $dispatchesEvents = [
         'created' => ProductCreated::class,
         'updated' => ProductUpdated::class,
@@ -125,9 +125,12 @@ class Product extends Model implements Purchasable
         });
     }
 
-    public function prices(): HasMany
+    public function prices(): MorphMany
     {
-        return $this->hasMany(config('shop.models.product_price', ProductPrice::class));
+        return $this->morphMany(
+            config('shop.models.product_price', ProductPrice::class),
+            'purchasable'
+        );
     }
 
     public function parent()
@@ -163,9 +166,17 @@ class Product extends Model implements Purchasable
         return $this->hasMany(config('shop.models.product_action', ProductAction::class));
     }
 
-    public function activeStocks(): HasMany
+    public function getAvailableStocksAttribute(): int
     {
-        return $this->stocks()->pending();
+        return $this->stocks()->available()->sum('quantity') ?? 0;
+    }
+
+    public function purchases(): MorphMany
+    {
+        return $this->morphMany(
+            config('shop.models.product_purchase', ProductPurchase::class),
+            'purchasable'
+        );
     }
 
     public function scopePublished($query)
@@ -180,10 +191,6 @@ class Product extends Model implements Purchasable
 
     public function isOnSale(): bool
     {
-        if (!$this->sale_price) {
-            return false;
-        }
-
         $now = now();
 
         if ($this->sale_start && $now->lt($this->sale_start)) {
@@ -207,30 +214,55 @@ class Product extends Model implements Purchasable
         return $defaultPrice ? $defaultPrice->price : $this->regular_price;
     }
 
+    public function isInStock(): bool
+    {
+        if (!$this->manage_stock) {
+            return true;
+        }
+
+        return $this->getAvailableStock() > 0;
+    }
+
     public function decreaseStock(int $quantity = 1): bool
     {
         if (!$this->manage_stock) {
             return true;
         }
 
-        if (config('shop.stock.log_changes', true)) {
-            $this->logStockChange(-$quantity, 'decrease');
+        if ($this->AvailableStocks < $quantity) {
+            return throw new NotEnoughStockException("Not enough stock available for product ID {$this->id}");
         }
 
+        $this->stocks()->create([
+            'quantity' => -$quantity,
+            'type' => 'decrease',
+            'status' => 'completed',
+        ]);
+
+        $this->logStockChange(-$quantity, 'decrease');
+
         $this->save();
 
         return true;
     }
 
-    public function increaseStock(int $quantity = 1): void
+    public function increaseStock(int $quantity = 1): bool
     {
         if (!$this->manage_stock) {
-            return;
+            return false;
         }
 
+        $this->stocks()->create([
+            'quantity' => $quantity,
+            'type' => 'increase',
+            'status' => 'completed',
+        ]);
+
         $this->logStockChange($quantity, 'increase');
 
         $this->save();
+
+        return true;
     }
 
     public function reserveStock(
@@ -257,7 +289,7 @@ class Product extends Model implements Purchasable
             return PHP_INT_MAX;
         }
 
-        return max(0, $this->stock_quantity);
+        return max(0, $this->AvailableStocks);
     }
 
     public function getReservedStock(): int
@@ -315,6 +347,17 @@ class Product extends Model implements Purchasable
         return $this->relatedProducts()->wherePivot('type', 'cross-sell');
     }
 
+    public function scopeInStock($query)
+    {
+        return $query->where(function ($q) {
+            $q->where('manage_stock', false)
+                ->orWhere(function ($q2) {
+                    $q2->where('manage_stock', true)
+                        ->whereRaw("(SELECT SUM(quantity) FROM " . config('shop.tables.product_stocks', 'product_stocks') . " WHERE product_id = " . config('shop.tables.products', 'products') . ".id) > 0");
+                });
+        });
+    }
+
     public function scopeVisible($query)
     {
         return $query->where('is_visible', true)
@@ -399,9 +442,6 @@ class Product extends Model implements Purchasable
             'regular_price' => $this->regular_price,
             'sale_price' => $this->sale_price,
             'is_on_sale' => $this->isOnSale(),
-            'in_stock' => $this->in_stock,
-            'stock_quantity' => $this->manage_stock ? $this->stock_quantity : null,
-            'stock_status' => $this->stock_status,
             'low_stock' => $this->isLowStock(),
             'featured' => $this->featured,
             'virtual' => $this->virtual,
@@ -456,4 +496,9 @@ class Product extends Model implements Purchasable
 
         return parent::newInstance($attributes, $exists);
     }
+
+    public function defaultPrice()
+    {
+        return $this->prices()->where('is_default', true);
+    }
 }
diff --git a/src/Models/ProductPrice.php b/src/Models/ProductPrice.php
index ebcc7c7..ac0b539 100644
--- a/src/Models/ProductPrice.php
+++ b/src/Models/ProductPrice.php
@@ -2,43 +2,48 @@
 
 namespace Blax\Shop\Models;
 
+use Blax\Shop\Contracts\Cartable;
+use Blax\Shop\Contracts\Purchasable;
 use Blax\Workkit\Traits\HasMetaTranslation;
 use Illuminate\Database\Eloquent\Concerns\HasUuids;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 
-class ProductPrice extends Model
+class ProductPrice extends Model implements Cartable
 {
-    use HasUuids, HasMetaTranslation;
+    use HasFactory, HasUuids, HasMetaTranslation;
 
     protected $fillable = [
-        'active',
-        'product_id',
+        'purchasable_type',
+        'purchasable_id',
         'stripe_price_id',
         'name',
         'type',
-        'price',
-        'sale_price',
+        'currency',
+        'unit_amount',
+        'sale_unit_amount',
         'is_default',
+        'active',
         'billing_scheme',
         'interval',
         'interval_count',
         'trial_period_days',
-        'currency',
         'meta',
     ];
 
     protected $casts = [
-        'price' => 'integer',
-        'sale_price' => 'integer',
         'is_default' => 'boolean',
-        'trial_period_days' => 'integer',
-        'meta' => 'object',
         'active' => 'boolean',
+        'meta' => 'object',
+        'unit_amount' => 'float',
+        'sale_unit_amount' => 'float',
+        'interval_count' => 'integer',
+        'trial_period_days' => 'integer',
     ];
 
-    public function product()
+    public function purchasable()
     {
-        return $this->belongsTo(Product::class);
+        return $this->morphTo();
     }
 
     public function scopeIsActive($query)
diff --git a/src/Models/ProductPurchase.php b/src/Models/ProductPurchase.php
index b226b7a..4bb1bc4 100644
--- a/src/Models/ProductPurchase.php
+++ b/src/Models/ProductPurchase.php
@@ -13,8 +13,10 @@ class ProductPurchase extends Model
         'status',
         'cart_id',
         'price_id',
-        'purchasable',
-        'purchaser',
+        'purchasable_id',
+        'purchasable_type',
+        'purchaser_id',
+        'purchaser_type',
         'quantity',
         'amount',
         'amount_paid',
@@ -37,12 +39,12 @@ class ProductPurchase extends Model
 
     public function purchasable()
     {
-        return $this->morphTo();
+        return $this->morphTo('purchasable');
     }
 
     public function purchaser()
     {
-        return $this->morphTo();
+        return $this->morphTo('purchaser');
     }
 
     public function product()
diff --git a/src/Models/ProductStock.php b/src/Models/ProductStock.php
index b7458b2..49c82f3 100644
--- a/src/Models/ProductStock.php
+++ b/src/Models/ProductStock.php
@@ -3,6 +3,7 @@
 namespace Blax\Shop\Models;
 
 use Blax\Shop\Models\Product;
+use Blax\Workkit\Traits\HasExpiration;
 use Illuminate\Database\Eloquent\Concerns\HasUuids;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
@@ -11,7 +12,7 @@ use Illuminate\Support\Facades\DB;
 
 class ProductStock extends Model
 {
-    use HasUuids;
+    use HasUuids, HasExpiration;
 
     protected $fillable = [
         'product_id',
@@ -70,16 +71,6 @@ class ProductStock extends Model
         return $query->where('status', 'completed');
     }
 
-    public function scopeExpired($query)
-    {
-        return $query->where('status', 'expired')
-            ->orWhere(function ($q) {
-                $q->where('status', 'pending')
-                    ->whereNotNull('expires_at')
-                    ->where('expires_at', '<=', now());
-            });
-    }
-
     public function scopeTemporary($query)
     {
         return $query->whereNotNull('expires_at');
@@ -216,4 +207,9 @@ class ProductStock extends Model
 
         return $count;
     }
+
+    public static function scopeAvailable($query)
+    {
+        return $query->where('status', 'completed');
+    }
 }
diff --git a/src/Traits/HasShoppingCapabilities.php b/src/Traits/HasShoppingCapabilities.php
index a570502..cf9d34f 100644
--- a/src/Traits/HasShoppingCapabilities.php
+++ b/src/Traits/HasShoppingCapabilities.php
@@ -2,31 +2,43 @@
 
 namespace Blax\Shop\Traits;
 
+use Blax\Shop\Exceptions\NotEnoughStockException;
+use Blax\Shop\Models\CartItem;
 use Blax\Shop\Models\ProductPurchase;
 use Blax\Shop\Models\Product;
 use Blax\Shop\Models\ProductPrice;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\Relations\MorphMany;
 use Illuminate\Support\Collection;
 
 trait HasShoppingCapabilities
 {
+    public function cart(): MorphMany
+    {
+        return $this->morphMany(
+            config('shop.models.cart', \Blax\Shop\Models\Cart::class),
+            'customer'
+        );
+    }
+
     /**
      * Get all purchases made by this entity
      */
     public function purchases(): MorphMany
     {
+        // This morph represents the purchaser (e.g. User), not the product.
         return $this->morphMany(
             config('shop.models.product_purchase', ProductPurchase::class),
-            'purchasable'
+            'purchaser'
         );
     }
 
     /**
      * Get cart items (purchases with status 'cart')
      */
-    public function cartItems(): MorphMany
+    public function cartItems(): HasMany
     {
-        return $this->purchases()->where('status', 'cart');
+        return $this->cart()->latest()->firstOrCreate()->items();
     }
 
     /**
@@ -50,16 +62,21 @@ trait HasShoppingCapabilities
         ProductPrice|string $productPrice,
         int $quantity = 1,
     ): ProductPurchase {
-        if ($productPrice instanceof ProductPrice) {
-        } else {
-            $productPrice = ProductPrice::findOrFail($productPrice);
-        }
 
-        if (!$productPrice?->product?->id) {
+        $productPrice = ($productPrice instanceof ProductPrice)
+            ? $productPrice
+            : ProductPrice::findOrFail($productPrice);
+
+        if (!$productPrice?->purchasable?->id) {
             throw new \Exception("Price does not belong to the specified product");
         }
 
-        $product = $productPrice->product;
+        $product = $productPrice->purchasable;
+        
+        // product must have interface Purchasable
+        if (!in_array('Blax\Shop\Contracts\Purchasable', class_implements($product))) {
+            throw new \Exception("The product is not purchasable");
+        }
 
         // Validate stock availability
         if ($product->manage_stock) {
@@ -81,7 +98,10 @@ trait HasShoppingCapabilities
 
         // Create purchase record
         $purchase = $this->purchases()->create([
-            'product_id' => $product->id,
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'purchaser_id' => $this->getKey(),
+            'purchaser_type' => get_class($this),
             'quantity' => $quantity,
             'status' => 'unpaid',
             'meta' => array_merge([
@@ -96,64 +116,48 @@ trait HasShoppingCapabilities
             'purchaser' => $this,
         ]);
 
+        $purchase->fresh();
+
+        if (!$purchase) {
+            throw new \Exception("Unable to create purchase record");
+        }
+
+        if (!$purchase->purchasable || $purchase->purchasable->id !== $product->id) {
+            throw new \Exception("Purchase record does not match the product");
+        }
+
         return $purchase;
     }
 
     /**
      * Add product to cart
      *
-     * @param Product $product
+     * @param Product|ProductPrice $price
      * @param int $quantity
      * @param array $options
-     * @return ProductPurchase
+     * @return CartItem
      * @throws \Exception
      */
-    public function addToCart(Product $product, int $quantity = 1, array $options = []): ProductPurchase
-    {
-        // Check if product already in cart
-        $existingItem = $this->cartItems()
-            ->where('product_id', $product->id)
-            ->first();
-
-        if ($existingItem) {
-            return $this->updateCartQuantity($existingItem, $existingItem->quantity + $quantity);
-        }
-
-        // Validate stock
-        if ($product->manage_stock && $product->getAvailableStock() < $quantity) {
-            throw new \Exception("Insufficient stock available");
-        }
-
-        $priceId = $options['price_id'] ?? null;
-        $price = $this->determinePurchasePrice($product, $priceId);
-
-        return $this->purchases()->create([
-            'product_id' => $product->id,
-            'quantity' => $quantity,
-            'status' => 'cart',
-            'meta' => array_merge([
-                'price_id' => $priceId,
-                'price' => $price,
-                'amount' => $price * $quantity,
-            ], $options['meta'] ?? []),
-        ]);
+    public function addToCart(Product|ProductPrice $price, int $quantity = 1, array $parameters = []): CartItem
+    {       
+        return $this->cart()->latest()->firstOrCreate()->addToCart(
+            $price,
+            $quantity,
+            $parameters
+        );
     }
 
     /**
      * Update cart item quantity
      *
-     * @param ProductPurchase $cartItem
+     * @param CartItem $cartItem
      * @param int $quantity
-     * @return ProductPurchase
+     * @return CartItem
      * @throws \Exception
      */
-    public function updateCartQuantity(ProductPurchase $cartItem, int $quantity): ProductPurchase
+    public function updateCartQuantity(CartItem $cartItem, int $quantity): CartItem
     {
-        if ($cartItem->status !== 'cart') {
-            throw new \Exception("Cannot update non-cart item");
-        }
-
-        $product = $cartItem->product;
+        $product = $cartItem->purchasable;
 
         // Validate stock
         if ($product->manage_stock && $product->getAvailableStock() < $quantity) {
@@ -161,15 +165,9 @@ trait HasShoppingCapabilities
         }
 
         $meta = (array) $cartItem->meta;
-        $priceId = $meta['price_id'] ?? null;
-        $price = $this->determinePurchasePrice($product, $priceId);
 
         $cartItem->update([
             'quantity' => $quantity,
-            'meta' => array_merge($meta, [
-                'price' => $price,
-                'amount' => $price * $quantity,
-            ]),
         ]);
 
         return $cartItem->fresh();
@@ -178,17 +176,13 @@ trait HasShoppingCapabilities
     /**
      * Remove item from cart
      *
-     * @param ProductPurchase $cartItem
+     * @param CartItem $cartItem
      * @return bool
      * @throws \Exception
      */
-    public function removeFromCart(ProductPurchase $cartItem): bool
+    public function removeFromCart(CartItem $cartItem): bool
     {
-        if ($cartItem->status !== 'cart') {
-            throw new \Exception("Cannot remove non-cart item");
-        }
-
-        return $cartItem->delete();
+        return $cartItem->forceDelete();
     }
 
     /**
@@ -237,56 +231,19 @@ trait HasShoppingCapabilities
      */
     public function checkout(?string $cartId = null, array $options = []): Collection
     {
-        $items = $this->cartItems()->with('product')->get();
+        $items = $this->cartItems()
+            ->with('purchasable')
+            ->get();
 
         if ($items->isEmpty()) {
             throw new \Exception("Cart is empty");
         }
 
-        // Validate stock for all items
-        foreach ($items as $item) {
-            $product = $item->product;
-            if ($product->manage_stock && $product->getAvailableStock() < $item->quantity) {
-                throw new \Exception("Insufficient stock for: {$product->getLocalized('name')}");
-            }
-        }
+        $purchases = collect();
 
-        // Process each item
-        $completedPurchases = collect();
-        foreach ($items as $item) {
-            $product = $item->product;
+        // 
 
-            // Decrease stock
-            if (!$product->decreaseStock($item->quantity)) {
-                // Rollback previous purchases
-                foreach ($completedPurchases as $purchase) {
-                    $purchase->product->increaseStock($purchase->quantity);
-                    $purchase->delete();
-                }
-                throw new \Exception("Unable to process checkout");
-            }
-
-            // Update status and store charge info in meta
-            $meta = array_merge((array) $item->meta, [
-                'charge_id' => $options['charge_id'] ?? null,
-                'completed_at' => now()->toISOString(),
-            ]);
-
-            $item->update([
-                'status' => 'completed',
-                'meta' => $meta,
-            ]);
-
-            // Trigger actions
-            $product->callActions('purchased', $item, [
-                'purchaser' => $this,
-                ...$options,
-            ]);
-
-            $completedPurchases->push($item);
-        }
-
-        return $completedPurchases;
+        return $purchases;
     }
 
     /**
diff --git a/tests/Feature/CartManagementTest.php b/tests/Feature/CartManagementTest.php
index d3188ec..e7f3c0c 100644
--- a/tests/Feature/CartManagementTest.php
+++ b/tests/Feature/CartManagementTest.php
@@ -5,6 +5,7 @@ namespace Blax\Shop\Tests\Feature;
 use Blax\Shop\Models\Cart;
 use Blax\Shop\Models\CartItem;
 use Blax\Shop\Models\Product;
+use Blax\Shop\Models\ProductPrice;
 use Blax\Shop\Tests\TestCase;
 use Illuminate\Foundation\Testing\RefreshDatabase;
 use Workbench\App\Models\User;
@@ -44,15 +45,21 @@ class CartManagementTest extends TestCase
     /** @test */
     public function it_can_add_items_to_cart()
     {
+        $product = Product::factory()->create();
+        $price = ProductPrice::factory()->create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+        ]);
+        
         $cart = Cart::create();
-        $product = Product::factory()->create(['price' => 99.99]);
-
+        
         $cartItem = CartItem::create([
             'cart_id' => $cart->id,
-            'product_id' => $product->id,
+            'purchasable_id' => $price->id,
+            'purchasable_type' => get_class($price),
             'quantity' => 2,
-            'price' => $product->price,
-            'subtotal' => $product->price * 2,
+            'price' => $price->unit_amount,
+            'subtotal' => $price->unit_amount * 2,
         ]);
 
         $this->assertCount(1, $cart->fresh()->items);
@@ -64,15 +71,13 @@ class CartManagementTest extends TestCase
     {
         $cart = Cart::create();
         $product = Product::factory()->create(['price' => 50.00]);
-
-        $cartItem = CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product->id,
-            'quantity' => 1,
-            'price' => $product->price,
-            'subtotal' => $product->price,
+        $price = ProductPrice::factory()->create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'unit_amount' => 50.00,
         ]);
 
+        $cartItem = $cart->addToCart($price, quantity: 1);
         $cartItem->update(['quantity' => 3]);
 
         $this->assertEquals(3, $cartItem->fresh()->quantity);
@@ -82,46 +87,44 @@ class CartManagementTest extends TestCase
     public function it_can_remove_items_from_cart()
     {
         $cart = Cart::create();
-        $product = Product::factory()->create(['price' => 75.00]);
-
-        $cartItem = CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product->id,
-            'quantity' => 1,
-            'price' => $product->price,
-            'subtotal' => $product->price,
+        $product = Product::factory()->create();
+        $price = ProductPrice::factory()->create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'unit_amount' => 100.00,
         ]);
 
-        $this->assertCount(1, $cart->fresh()->items);
+        $cartItem = $cart->addToCart($price, quantity: 1);
+
+        $this->assertCount(1, $cart->items);
 
         $cartItem->delete();
 
-        $this->assertCount(0, $cart->fresh()->items);
+        $this->assertCount(0, $cart->refresh()->items);
     }
 
     /** @test */
     public function it_calculates_cart_total_correctly()
     {
         $cart = Cart::create();
-        $product1 = Product::factory()->create(['price' => 50.00]);
-        $product2 = Product::factory()->create(['price' => 30.00]);
+        $product1 = Product::factory()->create();
+        $product2 = Product::factory()->create();
 
-        CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product1->id,
-            'quantity' => 2,
-            'price' => $product1->price,
-            'subtotal' => $product1->price * 2,
+        $productPrice1 = ProductPrice::factory()->create([
+            'purchasable_id' => $product1->id,
+            'purchasable_type' => get_class($product1),
+            'unit_amount' => 50.00,
         ]);
 
-        CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product2->id,
-            'quantity' => 1,
-            'price' => $product2->price,
-            'subtotal' => $product2->price,
+        $productPrice2 = ProductPrice::factory()->create([
+            'purchasable_id' => $product2->id,
+            'purchasable_type' => get_class($product2),
+            'unit_amount' => 30.00,
         ]);
 
+        $cart->addToCart($productPrice1, quantity: 2);
+        $cart->addToCart($productPrice2, quantity: 1);
+
         $total = $cart->fresh()->getTotal();
 
         $this->assertEquals(130.00, $total); // (50 * 2) + (30 * 1)
@@ -134,22 +137,21 @@ class CartManagementTest extends TestCase
         $product1 = Product::factory()->create();
         $product2 = Product::factory()->create();
 
-        CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product1->id,
-            'quantity' => 3,
-            'price' => 10.00,
-            'subtotal' => 30.00,
+        $product1Price = ProductPrice::factory()->create([
+            'purchasable_id' => $product1->id,
+            'purchasable_type' => get_class($product1),
+            'unit_amount' => 10.00,
         ]);
 
-        CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product2->id,
-            'quantity' => 2,
-            'price' => 20.00,
-            'subtotal' => 40.00,
+        $product2Price = ProductPrice::factory()->create([
+            'purchasable_id' => $product2->id,
+            'purchasable_type' => get_class($product2),
+            'unit_amount' => 20.00,
         ]);
 
+        $cart->addToCart($product1Price, quantity: 3);
+        $cart->addToCart($product2Price, quantity: 2);
+
         $totalItems = $cart->fresh()->getTotalItems();
 
         $this->assertEquals(5, $totalItems); // 3 + 2
@@ -238,16 +240,16 @@ class CartManagementTest extends TestCase
         $cart = Cart::create();
         $product = Product::factory()->create(['price' => 45.00]);
 
-        $cartItem = CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product->id,
-            'quantity' => 1,
-            'price' => $product->price,
-            'subtotal' => $product->price,
+        $productPrice = ProductPrice::factory()->create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'unit_amount' => 45.00,
         ]);
 
+        $cartItem = $cart->addToCart($productPrice, quantity: 1);
+
         $this->assertEquals($cart->id, $cartItem->cart->id);
-        $this->assertEquals($product->id, $cartItem->product->id);
+        $this->assertEquals($productPrice->id, $cartItem->purchasable_id);
     }
 
     /** @test */
@@ -256,14 +258,14 @@ class CartManagementTest extends TestCase
         $cart = Cart::create();
         $product = Product::factory()->create(['price' => 25.00]);
 
-        $cartItem = CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product->id,
-            'quantity' => 4,
-            'price' => $product->price,
-            'subtotal' => $product->price * 4,
+        $productPrice = ProductPrice::factory()->create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'unit_amount' => 25.00,
         ]);
 
+        $cartItem = $cart->addToCart($productPrice, quantity: 4);
+
         $this->assertEquals(100.00, $cartItem->getSubtotal()); // 25 * 4
     }
 
@@ -273,20 +275,23 @@ class CartManagementTest extends TestCase
         $cart = Cart::create();
         $product = Product::factory()->create();
 
-        $cartItem = CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product->id,
-            'quantity' => 1,
-            'price' => 50.00,
-            'subtotal' => 50.00,
-            'attributes' => [
-                'color' => 'blue',
-                'size' => 'large',
-            ],
+        $productPrice = ProductPrice::factory()->create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'unit_amount' => 50.00,
         ]);
 
-        $this->assertEquals('blue', $cartItem->attributes['color']);
-        $this->assertEquals('large', $cartItem->attributes['size']);
+        $cartItem = $cart->addToCart(
+            $productPrice, 
+            quantity: 1,
+            parameters: [
+                'color' => 'blue',
+                'size' => 'large',
+            ]
+        );
+
+        $this->assertEquals('blue', $cartItem->parameters['color']);
+        $this->assertEquals('large', $cartItem->parameters['size']);
     }
 
     /** @test */
@@ -295,23 +300,23 @@ class CartManagementTest extends TestCase
         $cart = Cart::create();
         $product = Product::factory()->create(['price' => 30.00]);
 
-        CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product->id,
-            'quantity' => 1,
-            'price' => $product->price,
-            'subtotal' => $product->price,
-            'attributes' => ['size' => 'small'],
+        $productPrice = ProductPrice::factory()->create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'unit_amount' => 30.00,
         ]);
 
-        CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product->id,
-            'quantity' => 2,
-            'price' => $product->price,
-            'subtotal' => $product->price * 2,
-            'attributes' => ['size' => 'large'],
-        ]);
+        $cart->addToCart(
+            $productPrice, 
+            quantity: 1,
+            parameters: ['size' => 'small']
+        );
+
+        $cart->addToCart(
+            $productPrice, 
+            quantity: 2,
+            parameters: ['size' => 'large']
+        );
 
         $this->assertCount(2, $cart->fresh()->items);
     }
@@ -322,14 +327,17 @@ class CartManagementTest extends TestCase
         $cart = Cart::create();
         $product = Product::factory()->create();
 
-        $cartItem = CartItem::create([
-            'cart_id' => $cart->id,
-            'product_id' => $product->id,
-            'quantity' => 1,
-            'price' => 50.00,
-            'subtotal' => 50.00,
+        $productPrice = ProductPrice::factory()->create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'unit_amount' => 75.00,
         ]);
 
+        $cartItem = $cart->addToCart(
+            $productPrice, 
+            quantity: 1,
+        );
+
         $cartItemId = $cartItem->id;
 
         $cart->forceDelete();
diff --git a/tests/Feature/ProductManagementTest.php b/tests/Feature/ProductManagementTest.php
index 9b4c7ce..42c1cc2 100644
--- a/tests/Feature/ProductManagementTest.php
+++ b/tests/Feature/ProductManagementTest.php
@@ -46,11 +46,11 @@ class ProductManagementTest extends TestCase
             'manage_stock' => true,
         ]);
 
-        $this->assertTrue($product->increaseStock(10));
-        $this->assertEquals(60, $product->fresh()->stock_quantity);
+        $this->assertTrue($product->increaseStock(60));
+        $this->assertEquals(60, $product->AvailableStocks);
 
         $this->assertTrue($product->decreaseStock(5));
-        $this->assertEquals(55, $product->fresh()->stock_quantity);
+        $this->assertEquals(55, $product->AvailableStocks);
     }
 
     /** @test */
@@ -58,11 +58,11 @@ class ProductManagementTest extends TestCase
     {
         $product = Product::factory()->create([
             'manage_stock' => true,
-            'stock_quantity' => 5,
         ]);
 
-        $this->assertFalse($product->decreaseStock(10));
-        $this->assertEquals(5, $product->fresh()->stock_quantity);
+        $this->assertThrows(function () use ($product) {
+            $product->decreaseStock(10);
+        }, \Blax\Shop\Exceptions\NotEnoughStockException::class);
     }
 
     /** @test */
@@ -70,10 +70,11 @@ class ProductManagementTest extends TestCase
     {
         $product = Product::factory()->create([
             'manage_stock' => true,
-            'stock_quantity' => 100,
         ]);
 
-        $this->assertEquals(100, $product->getAvailableStock());
+        $this->assertEquals(0, $product->getAvailableStock());
+        $product->increaseStock(20);
+        $this->assertEquals(20, $product->getAvailableStock());
     }
 
     /** @test */
@@ -81,14 +82,11 @@ class ProductManagementTest extends TestCase
     {
         $productInStock = Product::factory()->create([
             'manage_stock' => true,
-            'stock_quantity' => 10,
-            'in_stock' => true,
         ]);
+        $productInStock->increaseStock(10);
 
         $productOutOfStock = Product::factory()->create([
             'manage_stock' => true,
-            'stock_quantity' => 0,
-            'in_stock' => false,
         ]);
 
         $this->assertTrue($productInStock->isInStock());
@@ -128,7 +126,8 @@ class ProductManagementTest extends TestCase
         $product = Product::factory()->create();
 
         ProductPrice::create([
-            'product_id' => $product->id,
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
             'type' => 'one-time',
             'price' => 9999,
             'currency' => 'USD',
@@ -136,7 +135,8 @@ class ProductManagementTest extends TestCase
         ]);
 
         ProductPrice::create([
-            'product_id' => $product->id,
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
             'type' => 'recurring',
             'price' => 1999,
             'currency' => 'USD',
@@ -144,7 +144,7 @@ class ProductManagementTest extends TestCase
             'active' => true,
         ]);
 
-        $this->assertCount(2, $product->fresh()->prices);
+        $this->assertCount(2, $product->prices);
     }
 
     /** @test */
@@ -202,21 +202,20 @@ class ProductManagementTest extends TestCase
     public function it_can_scope_in_stock_products()
     {
         Product::factory()->create([
-            'in_stock' => true,
-            'manage_stock' => true,
-            'stock_quantity' => 10,
+            'manage_stock' => false,
         ]);
 
-        Product::factory()->create([
-            'in_stock' => false,
+        $productInStock = Product::factory()->create([
             'manage_stock' => true,
-            'stock_quantity' => 0,
         ]);
+        $productInStock->increaseStock(10);
 
         $inStock = Product::inStock()->get();
 
-        $this->assertCount(1, $inStock);
-        $this->assertTrue($inStock->first()->in_stock);
+        $this->assertCount(2, $inStock);
+        $this->assertTrue((bool) ($inStock->first()->isInStock()));
+        $this->assertNotEquals($inStock->reverse()->first()->id, $inStock->first()->id);
+        $this->assertTrue((bool) ($inStock->reverse()->first()->isInStock()));
     }
 
     /** @test */
diff --git a/tests/Feature/PurchaseFlowTest.php b/tests/Feature/PurchaseFlowTest.php
index d85514e..d359f8e 100644
--- a/tests/Feature/PurchaseFlowTest.php
+++ b/tests/Feature/PurchaseFlowTest.php
@@ -2,9 +2,12 @@
 
 namespace Blax\Shop\Tests\Feature;
 
+use Blax\Shop\Exceptions\NotEnoughStockException;
 use Blax\Shop\Models\Product;
 use Blax\Shop\Models\ProductPurchase;
+use Blax\Shop\Models\ProductPrice;
 use Blax\Shop\Models\Cart;
+use Blax\Shop\Models\CartItem;
 use Blax\Shop\Tests\TestCase;
 use Illuminate\Foundation\Testing\RefreshDatabase;
 use Workbench\App\Models\User;
@@ -18,17 +21,23 @@ class PurchaseFlowTest extends TestCase
     {
         $user = User::factory()->create();
         $product = Product::factory()->create([
-            'price' => 99.99,
             'manage_stock' => false,
         ]);
 
-        $purchase = $user->purchase($product, quantity: 1);
+        $price = ProductPrice::create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'amount' => 4999, // in cents
+            'currency' => 'USD',
+        ]);
+        
+        $purchase = $user->purchase($price, quantity: 1);
 
         $this->assertInstanceOf(ProductPurchase::class, $purchase);
-        $this->assertEquals($product->id, $purchase->product_id);
-        $this->assertEquals($user->id, $purchase->user_id);
+        $this->assertEquals($product->id, $purchase->purchasable_id);
+        $this->assertEquals($user->id, $purchase->purchaser_id);
         $this->assertEquals(1, $purchase->quantity);
-        $this->assertEquals('completed', $purchase->status);
+        $this->assertEquals('unpaid', $purchase->status);
     }
 
     /** @test */
@@ -36,27 +45,36 @@ class PurchaseFlowTest extends TestCase
     {
         $user = User::factory()->create();
         $product = Product::factory()->create([
-            'price' => 49.99,
             'manage_stock' => false,
         ]);
 
-        $cartItem = $user->addToCart($product, quantity: 2);
+        $price = ProductPrice::create([
+            'purchasable_id' => $product->id,
+            'purchasable_type' => get_class($product),
+            'amount' => 2999, // in cents
+            'currency' => 'USD',
+            'is_default' => true,
+        ]);
 
-        $this->assertInstanceOf(ProductPurchase::class, $cartItem);
-        $this->assertEquals('cart', $cartItem->status);
+        $cartItem = $user->addToCart($price, quantity: 2);
+
+        $this->assertInstanceOf(CartItem::class, $cartItem);
         $this->assertEquals(2, $cartItem->quantity);
-        $this->assertEquals($product->id, $cartItem->product_id);
+        $this->assertEquals($price->id, $cartItem->purchasable_id);
     }
 
     /** @test */
     public function user_can_get_cart_items()
     {
         $user = User::factory()->create();
-        $product1 = Product::factory()->create(['price' => 20.00]);
-        $product2 = Product::factory()->create(['price' => 30.00]);
+        $product1 = Product::factory()->withPrices()->create();
+        $product2 = Product::factory()->withPrices(2)->create();
 
-        $user->addToCart($product1, quantity: 1);
-        $user->addToCart($product2, quantity: 2);
+        $this->assertCount(1, $product1->prices);
+        $this->assertCount(2, $product2->prices);
+
+        $user->addToCart($product1->prices()->first(), quantity: 1);
+        $user->addToCart($product2->prices()->first(), quantity: 2);
 
         $cartItems = $user->cartItems;
 
@@ -67,12 +85,9 @@ class PurchaseFlowTest extends TestCase
     public function user_can_update_cart_item_quantity()
     {
         $user = User::factory()->create();
-        $product = Product::factory()->create([
-            'price' => 50.00,
-            'manage_stock' => false,
-        ]);
+        $product = Product::factory()->withPrices()->create();
 
-        $cartItem = $user->addToCart($product, quantity: 1);
+        $cartItem = $user->addToCart($product->prices()->first(), quantity: 1);
 
         $user->updateCartQuantity($cartItem, quantity: 5);
 
@@ -83,32 +98,32 @@ class PurchaseFlowTest extends TestCase
     public function user_can_remove_item_from_cart()
     {
         $user = User::factory()->create();
-        $product = Product::factory()->create();
+        $product = Product::factory()->withPrices()->create();
 
-        $cartItem = $user->addToCart($product, quantity: 1);
-        $this->assertCount(1, $user->fresh()->cartItems);
+        $cartItem = $user->addToCart($product->prices()->first(), quantity: 1);
+
+        $this->assertCount(1, $user->cartItems);
 
         $user->removeFromCart($cartItem);
 
-        $this->assertCount(0, $user->fresh()->cartItems);
+        $this->assertCount(0, $user->refresh()->cartItems);
     }
 
     /** @test */
     public function user_can_checkout_cart()
     {
         $user = User::factory()->create();
-        $product1 = Product::factory()->create([
-            'price' => 25.00,
-            'manage_stock' => false,
-        ]);
-        $product2 = Product::factory()->create([
-            'price' => 35.00,
-            'manage_stock' => false,
-        ]);
+        $product1 = Product::factory()->withPrices()->create();
+        $product2 = Product::factory()->withPrices()->create();
 
         $user->addToCart($product1, quantity: 2);
         $user->addToCart($product2, quantity: 1);
 
+        $this->assertThrows(fn() => $user->checkout(), NotEnoughStockException::class);
+
+        $product1->update(['manage_stock' => false]);
+        $product2->increaseStock(5);
+
         $purchases = $user->checkout();
 
         $this->assertCount(2, $purchases);