The module supports something we have called a “Variable price product”. In other words, it is a product with no fixed price. This can be used for donations and similar activities. Since it is part of the module, you can order a range of products, where one of the products is a variable price one.
To use a variable price product, you must first check the “Is variable price product” on the product. Then you have to add the “AddVariablePriceProductToCartTemplate” template to the “AddToCart” control. The system control finds the price from a control called txtPrice in that template.
You can also add a variable price product to the cart manually by calling the WAFShopHelper.AddVariablePriceProductToCart method. The method signature looks like this;
AddVariablePriceProductToCart(int productId, double priceIncVat, Guid orderGuid, int userId)
As you can see above, you can only add one of each product id to the cart at the same time when you're using the variable price products.