Here is the problem:

When prices are being solely managed by product attributes the prices are not reflected in the category screen and a customer can add the item to the shopping cart and purchase this item at no cost.

If one has categories set up, but is managing products prices by attributes and none of the attributes are required: a customer can choose the category and the product variant will show up as 0 cost on the product category menu because it does not pick up the attribute costs.  If a customer chooses to add the this product variant to the cart directly from the category menu, the program adds the product variant to the shopping cart for 0 cost; and the customer can place the order for the default quantity at 0 cost!  

The solution is to have an option to disable or hide the "add to cart button"  in the product category screen; or if the variant is being managed by attributes pricing, that the program checks the attribute pricing before it adds the variant to cart.

I consider this a serious flaw that will cost businesses using nopCommerce money.  In fact it is such a serious accounting flaw that I those not using nopCommerce should probably consider using another shopping cart until it is corrected.   Anything that allows a customer to bypass and add products at 0 cost should not be considered for serious live e-commerce site.

This flaw needs to be fixed.  Customers should not be allowed to bypass attribute pricing.

To Duplicate:

1.  Create a product: Hotel Madrid, Choose Variants in Grid; and PV: One Night Stay; manage inventory by product attribute;  set price to $0 on both the product and product variant.

2.  Create the following attributes:  7 July 2011;

3. Under PV add the 7 July 2011 attribute and choose check-box control

4. Under the 7 July 2011 attribute select edit and add the following new values: Room Double, $125, pre-select; and Room Single, $100; no pre-selection.  If you want you can group the attributes.  Make sure required is NOT selected in any of the attributes.

5. Create an Accommodation category and add the product to the category.

6. Turn on Dynamic Pricing from the global settings.  

7. Go to the public site and choose the accommodation category.

8.  The Hotel Madrid will show up in the category's menu with 0 cost.

9. Choose add to cart from the category.

10.  The product will be entered to cart for purchasing at zero cost.

11.  If you go to the product menu you will see the correct price of $125 for the preselected type. When added to cart from the product page the price of the item is correct.

The site should now display the stated behavior.  It is now possible to add 1 zero priced item to the cart from the category menu although the the price is reflected properly on the product details page.

I have a live e-commerce site and it is displaying this behavior.

A detailed discussion on the issue can be found in the following thread.  The behavior is confirmed by eadameg:

https://www.nopcommerce.com/boards/t/9774/hide-base-price-of-productspricing-issues.aspx