There was a time when buying a car online was a bit of an oddity. It sure seemed strange to me when I did it some two or three years ago. (Who can remember at this point?) Now its anything but rare, as signified by eBay Motors' recent announcement that its three millionth passenger vehicle has sold in the US. In celebration, eBay Motors refunded the purchase price, which sounds like a pretty good deal even if the vehicle in question was a Ford truck. Launched as a formal category in 2000, ebaymotors.com, a part of eBay Inc., is now the Internet's largest marketplace for buying and selling all things automotive. How large is the arena? According to the company, a passenger vehicle sells on the site every 56 seconds. That means there's a good chance at least a few of you have bought some of those cars, so let's hear about it, good, bad, or indifferent.