I have a basic Upload script where a user Browses his desktop, selects a file to upload and Submits it. And then returns to any page I direct them to. I'd like to modify this so that the user is required to first make a small paypal payment before uploading is allowed, each time. Any thoughts on how I might accomplish this? Thanks.
first check if the cookie exists, if yes then show the upload script, if not, show the donate button, and in paypal you have an option to redirect the user to a page you choose when the transaction is completed, so use that option and redirect him to a page that set the cookie.
Since he wants to have them pay for every upload, he would have to make sure he expires the cookie after the upload then.
You'd probably want to use paypal for this, as they offer several solutions that will integrate into your application easily. This is where you should start.