Ebay, cars.com and autotrader. I pefer Ebay by a long shot, becuase the sellers are much more honest about condition since they worry about their Ebay reputation. I don't like to buy sight unseen and usually look for ebay cars in my area that I can go see. A good trick I use is if I like the car, I will ask to use the dealers computer so that I can hit the "buy it now" . Once you have done this the dealer is stuck making good on all promises until you leave feedback. I had one dealer try to get me to leave positive feedback before taking care of a few items. He was mad when he realiazed I wouldn't do so until everything that was agreed was completed. The other two sites have cars that are dissappointments much of the time. Keep in mind that most scratches won't show up in pictures.