Beepi lets you list your car and get a price that is guaranteed to be above what you can get from a dealership. Beepi takes care of the entire used car selling process, it even buys it from you if not sold in 30 days. If after sold your used car, you want to get another car, you can even get $600 coupon from Beepi.
Sounds like a good used car marketplace for consumers.