There arent that many scammers on eBay but the ones there are tend to be greedy. This means that they will always try to pull their scams on high-value items like cars and computers, so that they can make a lot of money quickly. Since buyers generally buy these items very rarely, they may not know about the various scams out there.
Automobile Scams.
With cars, you will generally find that scammers try to get you to send them money in advance, for whatever reason. For some reason, some people arent all that reluctant to pay 50% or 25% of the money before delivery using a relatively insecure payment method, especially on a car. They reason that the seller will obviously deliver it, as theyll want the other half of the money.
But there never was a car! Pictures of cars arent hard to find, and the experienced scammers will have a whole library of pictures of different cars. The seller just got your $5,000 for nothing, and you can leave them all the negative feedback you like. Theyll just go and open another eBay account and find their next sucker.
While its not an outright scam, what you might find is that the car does turn up, but simply doesnt live up...