Can I pre-fill an amount for a user defined price? I'm trying to use Cart66 for customer invoices so each price would be different. I have set up a user-defined product (INV101) and would like to add the shortcode to their invoice pages. I'd like to be able to pre-fill the amount with the amount I want them to pay.
example shortcode is:
add_to_cart item="INV101" quantity="user:1" text="Add To Cart"