I don't know. I just tell'em there a fee: $150 if we find you a lead / buyer from our site. They say stuff like, ok cars sucks and they get spammed to hell with craiglist and some say autotrader charges them a fee upfront. Then i gotta track them down, its not easy but i am making money. Next move is to figure out a upfront price. I just want to grab a slice from cars, auto trader, craiglist ONLY for used tesla cars.