diff --git a/src/main/java/com/back/domain/cart/entity/Cart.java b/src/main/java/com/back/domain/cart/entity/Cart.java
index b6713981..70c8b9d0 100644
--- a/src/main/java/com/back/domain/cart/entity/Cart.java
+++ b/src/main/java/com/back/domain/cart/entity/Cart.java
@@ -126,43 +126,49 @@ public boolean isFundingCart() {
         return this.cartType == CartType.FUNDING;
     }
 
-    // 유효한 장바구니 아이템인지 확인
+    // 유효한 장바구니 아이템인지 확인 (null-safe)
     public boolean isValid() {
-        // 수량 검증
-        if (this.quantity <= 0) {
+        // 1) 수량 검증 (null 또는 1 미만이면 무효)
+        if (this.quantity == null || this.quantity <= 0) {
             return false;
         }
-        
+
+        // 2) 펀딩 장바구니 검증
         if (isFundingCart()) {
-            // 펀딩 장바구니 검증
             if (this.funding == null) {
                 return false;
             }
-            // fundingStock이 설정되어 있으면 그것을 기준으로, 없으면 funding의 stock 사용
-            int availableStock = (this.fundingStock != null) ? this.fundingStock : this.funding.getStock();
-            return this.quantity <= availableStock;
-        } else {
-            // 일반 장바구니 검증
-            if (this.product == null) {
-                return false;
-            }
-            
-            // 상품이 삭제되지 않았고 재고가 있는지
-            if (this.product.isDeleted() || this.product.getStock() <= 0) {
+            Integer fundingStockFromEntity = this.funding.getStock();
+            int availableStock = (this.fundingStock != null)
+                    ? this.fundingStock
+                    : (fundingStockFromEntity != null ? fundingStockFromEntity : 0);
+
+            if (availableStock <= 0) {
                 return false;
             }
-            
-            // 일반 재고 확인
-            return this.quantity <= this.product.getStock();
+            return this.quantity <= availableStock;
+        }
+
+        // 3) 일반 장바구니 검증
+        if (this.product == null) {
+            return false;
         }
+        if (this.product.isDeleted()) {
+            return false;
+        }
+        Integer productStock = this.product.getStock();
+        if (productStock == null || productStock <= 0) {
+            return false;
+        }
+        return this.quantity <= productStock;
     }
 
-    // 총 가격 계산
+    // 총 가격 계산 (null-safe)
     public int getTotalPrice() {
+        int qty = (this.quantity != null && this.quantity > 0) ? this.quantity : 0;
         int unitPrice;
-        
+
         if (isFundingCart()) {
-            // 펀딩 장바구니: fundingPrice 사용
             if (this.fundingPrice != null) {
                 unitPrice = this.fundingPrice;
             } else if (this.funding != null) {
@@ -171,14 +177,21 @@ public int getTotalPrice() {
                 return 0;
             }
         } else {
-            // 일반 장바구니: Product 가격 사용
             if (this.product == null) {
                 return 0;
             }
-            unitPrice = this.product.getDiscountPrice();
+            Integer discount = this.product.getDiscountPrice();
+            Integer basePrice = this.product.getPrice();
+            if (discount != null) {
+                unitPrice = discount;
+            } else if (basePrice != null) {
+                unitPrice = basePrice;
+            } else {
+                return 0;
+            }
         }
-        
-        return unitPrice * this.quantity;
+
+        return unitPrice * qty;
     }
 
     // ===== 도메인 메서드 (선택 상태 조회) =====
diff --git a/src/main/java/com/back/domain/cart/service/CartService.java b/src/main/java/com/back/domain/cart/service/CartService.java
index e1a405d0..45c5bd6d 100644
--- a/src/main/java/com/back/domain/cart/service/CartService.java
+++ b/src/main/java/com/back/domain/cart/service/CartService.java
@@ -298,6 +298,9 @@ public void validateCartItemsForOrder(User user, boolean isFullOrder) {
             throw new ServiceException("CART_EMPTY", "주문할 장바구니 아이템이 없습니다.");
         }
 
+        // 레거시 데이터 보정 (펀딩 price/stock 누락 대비)
+        cartItems.forEach(this::normalizeCartFields);
+
         // 각 아이템의 유효성 검증
         for (Cart cart : cartItems) {
             if (!cart.isValid()) {
@@ -319,13 +322,35 @@ public void validateCartItemsForOrder(User user, boolean isFullOrder) {
         }
     }
 
+    private void normalizeCartFields(Cart cart) {
+        if (cart.isFundingCart() && cart.getFunding() != null) {
+            if (cart.getFundingPrice() == null) {
+                cart.updateFundingInfo(
+                        cart.getFundingId(),
+                        (int) cart.getFunding().getPrice(),
+                        cart.getFundingStock()
+                );
+            }
+            if (cart.getFundingStock() == null) {
+                cart.updateFundingInfo(
+                        cart.getFundingId(),
+                        cart.getFundingPrice(),
+                        cart.getFunding().getStock()
+                );
+            }
+        }
+    }
+
     /**
      * 장바구니 총 금액 계산 (전체/선택)
      */
     public Integer calculateTotalAmount(User user, boolean isFullOrder) {
         List<Cart> cartItems = isFullOrder ? 
             cartRepository.findByUserWithProduct(user) :
-            cartRepository.findByUserAndIsSelectedTrue(user);
+            cartRepository.findByUserAndIsSelectedTrueWithProduct(user);
+
+        // 레거시 보정(펀딩 price/stock 누락 대비)
+        cartItems.forEach(this::normalizeCartFields);
 
         return cartItems.stream()
             .filter(Cart::isValid)
diff --git a/src/test/java/com/back/domain/cart/service/CartServiceTest.java b/src/test/java/com/back/domain/cart/service/CartServiceTest.java
index fee30e65..ffd7273a 100644
--- a/src/test/java/com/back/domain/cart/service/CartServiceTest.java
+++ b/src/test/java/com/back/domain/cart/service/CartServiceTest.java
@@ -560,12 +560,12 @@ void validateCartItemsForOrder_SelectedOrder_Success() {
         // Given
         testNormalCart.select();
         List<Cart> selectedCarts = Arrays.asList(testNormalCart);
-        given(cartRepository.findByUserAndIsSelectedTrue(testUser)).willReturn(selectedCarts);
+        given(cartRepository.findByUserAndIsSelectedTrueWithProduct(testUser)).willReturn(selectedCarts);
 
         // When & Then
         cartService.validateCartItemsForOrder(testUser, false);
         
-        verify(cartRepository).findByUserAndIsSelectedTrue(testUser);
+        verify(cartRepository).findByUserAndIsSelectedTrueWithProduct(testUser);
     }
 
     @Test
@@ -601,14 +601,14 @@ void calculateTotalAmount_SelectedOrder_Success() {
         // Given
         testNormalCart.select();
         List<Cart> selectedCarts = Arrays.asList(testNormalCart);
-        given(cartRepository.findByUserAndIsSelectedTrue(testUser)).willReturn(selectedCarts);
+        given(cartRepository.findByUserAndIsSelectedTrueWithProduct(testUser)).willReturn(selectedCarts);
 
         // When
         Integer result = cartService.calculateTotalAmount(testUser, false);
 
         // Then
         assertThat(result).isNotNull();
-        verify(cartRepository).findByUserAndIsSelectedTrue(testUser);
+        verify(cartRepository).findByUserAndIsSelectedTrueWithProduct(testUser);
     }
 
     @Test