A product has a set price and we offer "customize this product", by using the "Ask a question" contribution, we email them back with an additional price.
How can they add the additional price to the order in the ordering process?
Example:
Customer wants this product but with a different colored shirt and writing on it.
So, the customer hits "Customize this product" sidebox link and we respond back with the additional cost of $20.00 to the original price of $89.00
Here is a product page from the site



