Most of my experience is in the price range north of $400K and the rates I've seen are 4% for a basic service and 5% for a full on marketing of the aircraft including mailings and all the classified outlets. It depends on what you're looking for. If you're willing to meet all the tire kickers and do most of the work yourself you shouldn't pay much for someone just to handle the transaction. But if you're looking for someone to aggressively market your airplane, take all the calls, weed out the dreamers and tire kickers, qualify them financially, arrange for whatever training the buyer might need to own your plane, ... then that stuff costs a lot regardless of the value of your plane and you should expect to pay for it - and when you do, get it. Finding a good broker is a tougher question to answer 'cause their rare as hen's teeth.