php/html paypal button

I have a page that takes a get keyword, then prompts if they would like to purchase or continue. The issue is that I am trying to set it up to automatically perform the service once they do the paypal purchase. The buy now button they provide doesnt allow me to dynamically set the success redirect page so I am unable to pass the keyword onto the page that delivers the service.

So for an example

http://website.com/test.php?keyword=waffles

On that page it will display: "Do you want to buy waffles? [Paypal Button]"

I need to be able to pass on the keyword waffles onto the success page. The only alternative I can th开发者_开发技巧ink of is a bad idea. Logging the ip and keyword the button click. Then when the success page is shown, it gets the ip and keyword logged. Of course that is too risky since someone's ip can change and they will lose the purchase after paying.

You could try to use a session. :)

http://php.net/manual/en/features.sessions.php