A friend of mine is trying to sell his car. He says that he prefers to transact with direct buyers instead of going through agents/referrals because they would ask for a "finder's fee" (in other words, commission).
It's been months but he's still having difficulty looking for buyers of his car. He says that he now looks inclined to seek the help of car sales agents. He is asking how much would be a fair "finder's fee"?