Help needed with coupon entry for PayPal Buttons

[bethperkins]

My client needs to switch from PayPal Pro Forms to PayPal Buttons in the final stage of project and we need to provide the ability to enter coupons. The process is simple - people will have the option to enter a coupon code which will entitle them to a free trial, otherwise they will be billed immediately. The other requirement is that my client needs to track usage of the codes. For this reason, I was thinking of a simple JS or PHP program that would
1 - verify that the code is correct
2- if code is correct, use PHP to pass it to page containing button (that includes free trial) as a variable so that we can use Google Analytics to track usage
3 - if customer does not have coupon code, they would only have option of clicking button (without free trial) on the original page
Can someone point me to some logic that I can use as the base for this process? Or recommend a better alternative? We have the S2Member Pro version although we now need to use PayPal buttons.
Solution is needed quickly and any offer of help would be appreciated!

[Cristián Lávaque]

Hi Beth.

Maybe this gives you an idea to achieve what you need? viewtopic.php?f=4&t=16176&p=54503#p54503

I hope it helps.