You CAN buy a car on EBAY and not lose your shirt. However, the way to do this is to find a car and a seller on there that you can check out in person or through a trusted agent.
Otherwise, it is a crap shoot. Emphasis on crap, huh?
I have sold several cars by listing on EBAY and having a local or regional buyer show up to buy the car in person. That way, I won and they won.
