Simple Paypal Shopping Cart Script Wanted

[jdk]

I am looking for a simple php Paypal shopping cart script that I can incorporate into one of my sites. I am currently using Paypal's shopping cart buttons, but I want to add the ability to create custom coupon codes to allow for discounts that Paypal by iteself doesn't support.

Can anyone recommend a stand alone script?

 

[south]

http://www.opencart.com/index.php?route=feature/feature