PeoAdult has that option via their s-revenue program you can set a payout to the people promoting your sites your decide what the payout should be for each different kind of sale (1 year, 2 year, web900 ect.) Its not a "free" program!
s-revenue is an option on both regular and Quantum sites (like gold/platnium)
http://www.adultverifier.com have the same option on their Ultra sites (gold/Platinium)
They are the only ones I know that offer this AgeOath offer something like this with their gold/platinium sites but they are dead now
I havenīt heard of any "free" AVS that offers this.
Keyser