Buying a car on eBay can be a satisfying experience providing that you buy from an honest person who has lots of good feedback and describes the car or truck accurately. Aside from multiple positive feedback, I'd say at least 30 or more and a good rating, say 97 or better, the feedback should be from selling as well as buying so you can see how they treat buyers.
The ad for the car or truck for sale on Ebay should have tons of photos from every angle and of any dents or scratches.
You should do a Carfax report on the car with the VIN number provided and see if it has had any accidents. For a while there were a few cars from Katrina flooding on Ebay which had water damage.
Carfax should show a history of the car from every owner.
Inquire as to whether the car belongs to the person who is listing it on Ebay. It should our you could have problems. It should also have a free and clear title with no mechanics liens, etc.
There are commercial companies that will offer to ship for you. Get a quote prior to bidding. You may also want to get a company such as "Lemon Busters" to come out and do an in depth check of the car before bidding. Any Ebay seller not wanting you to do this should be avoided since they probably have something to hide.
Inquire about service records including oil changes and transmission fluid changes. Ask what the tread wear is as well. Again, a reputable Lemon Busters service should give you a complete checkup of the car for a little over a hundred dollars but it could save you thousands.
Check out the NADA Blue Book Value site and bookmark their site to aid in knowing what the fair value of the car is.