I will be introducing some merchandise on my website soon and was looking to have a reward system for users who refer other friends. So for example if a user refers X number of friends and Y number of them sign-up OR Z number of them purchase an item I reward that user with a free item. Can someone help me out by suggesting a PHP script or something that can do that for me ? That will be much easier for me instead of writing the script myself. If this is the wrong place to ask this question then I apologize.