simple affiliate program

[yayvb]

It's very simple.
User refers someone.
Admin can decide to pay once or life of customer sort of thing.
First option, if user ever becomes a paying subscriber, the referer will make the specified amount. Second option, if user continues paying, the referer will make an amount each time the subscription is renewed.

Perhaps allow members to see who they've referred (signups) and who they've earned from (paying signups).