[tom406]

That 5% number sounds fair and about right. That's assuming you did some real legwork and found something that the fellow couldn't or wouldn't find on his own, and pretty much lined it all up. Passing on phone numbers or introducing people would be less compensated (somewhere between 4.9% and a heartfelt "Thanks buddy"). Whatever you do, its good to be upfront with your ideas or expectations, so that both parties are pleased with the deal, and might continue to work together in the future (and to avoid those years-long grudges over perceived slights).