What is a fair finder fee?

A buddy of mine found me a '91 Mansion, 3/2, for $8K. Good condition, all appliances, A/C, shed. He has negotiated the price down to $6,500 and is putting it under contract tomorrow with $250. His contract reads “as agent for Rolf Jacobs” so that it goes directly into my name. The people need 2-3 weeks to finish purchase of their new home before they move out. All in all, I think he did a good job for his first time doing this and I want to compensate him well so that he will turn up others. He will make sure the home is in the same condition when the sellers move out and then give them a cashier’s check for the balance. At that point his involvement is done and then I bring in the mover.

Can I get some feedback as to what would be a fair amount to pay him for his work? I want to make it worth his while to turn up more of these for me but I don’t want to overpay him for his work.

Thanks.

Rolf

Wheat Hill