Pay Per Download
With Pay per Download component you can control access to resources on your site based on users’ membership. You can have different types of memberships, with different levels, prices and expiration dates. Memberships are payed using Paypal IPN.
Thanks to Olivier Buisard for bug fixes.
Tested on PHP 5.2.17, mySQL 5.1.58-community-log. Make sure you have least these requirements.