[onewhippedpuppy]

There are plenty of online escrow services that offer this exact service for a small fee. It's really only necessary for sight unseen purchases.

Even simpler is to conduct the transaction with a cashier's check at your bank, have the bank verify funds before you sign over the title. Or have the buyer complete a wire transfer after inspecting the car, you sign over the title when the wire clears. Or just do cash, that's as simple as it gets.