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I need to be able to allow visitors to a Prestashop website that I'm working on to receive pricing for custom frames in real-time based on their painting's size. I need to be able to enter the price per inch for each frame style/product on the Prestashop back-end and the user needs to be able to enter the length and width of their painting using form fields on the product page. When user clicks Update, the price for the frame should update and they should have the option of adding it to their cart. I used Prestashop 1.5.6.2 Similar site: [login to view URL]