Basically im going to start a site where plenty of people will register and be members... but when someone sign up under another person they first person gets a percentage of the item bought
example:
User1 signs up> User1 tells User2 to sign up> User2 signs up through User1 (some type of reference code or enter their name when signing up?)> User2 buys something> User1 get %10 of what User2 bought>
Is it any type of modules available to do this?