Order form with integrated calculator


Hi everyone, Im creating a webstore where i sale large format prints. Each order will be bases on custom sizes. I need this calculator on the website: https://www.aprintco.com/index.php?route=product/product&product_id=269 depending on the size then price is calculated and the depending on small addition the add 5 or 10 additional dollars.

Does anyone know of a plugin within envato that i can purchase. If not available on envato, can some one give me a ballpark estimate on this.

thank you