I have a typical Zen Cart e-commerce store. We sell custom picture frames. We currently place 9 different standard sizes for customers to choose from and add them to their cart. The problem is we sell custom picture frames (which means the customer could have any size they want). I need the PHP changed to allow the customer to go to a particular frame , enter in the size they want and have it display the price. Then if they choose to add it to the shopping cart. I have a equation to calculate the price of the frame when the client puts in the height and width. It is a simple equation that we use in excel. The version of Zen Cart is the latest version.