Plenty to add here...

Carfax is not the end-all of car histories. A car can be wrecked and not reported depending on what state you're in, what kind of insurance the car's owner had, and other factors. Flood damage and fire damage may not be reported to an insurance company or government agency and therefore will not show up on the CarFax. A DMV clerk could mistype a number on a title application and show an odometer discrepancy. My parents gave me an old Buick once, and when I bought the car, it showed 224,220 miles. That is what went on the title when we got it notarized. When I returned home, I had to inspect the car before it could be titled in my state. The inspection occured at 226,700 miles. That inspection was reported to CarFax. Then when I titled the car two weeks later, the 224,220 number was reported to CarFax on that day. Forevermore, that car has been branded by CarFax with an odometer discrepancy, even though it was a simple clerical error and the odometer had never been tampered with.

eBay is a fun place to buy a car, but beware of the thousands of scam artists and the shady backlot dealers that populate it. The best bet to buying a common car on eBay is to only search local auctions where you can inspect the car BEFORE you buy. Obviously, if you're looking for a 1979 Grand Prix with T-tops and red buckets and console, and the only one on eBay equipped as such is 1200 miles away, you have little choice in the matter. I've bought 11 vehicles on eBay, 9 of them operable, and none costing more than $400 or so. I'm very pleased with those purchases and will continue to search eBay for the elusive $100 cars that run and drive that I have enjoyed in the past. My last eBay purchase was a 1970 Ford pickup truck in horrible but running shape for $406. I got plenty of use out of it for most of 2004 before it was stolen from me, but since I never bothered to re-title it, I couldn't get it back when the police found it (intact, mind you). It sold at the impound auction for $900 (more than I had on hand, I ended up buying a $300 Chevy Celebrity that day to get me to work) and I still see it around occasionally.

As far as used taxicabs, I don't see anything wrong with buying them. If you need basic transportation and don't mind the color, a used Crown Vic taxi can be a great ride. In New York, they pull the cabs off after 3 years of use. So for about $2500, you can get a 2004-2005 model Crown Vic with 200-250K on it. Compare that to the $12500 you'd spend on a non-taxi or the fact that $2500 barely gets you a ten-year old Crown Vic, and it's a steal. In Chicago, think more like 5 years and 300-400K miles, but also think $1000-$1500 to buy it. I would love to start a business buying ex-Chicago cabs for $1000 each, truck them to Texas, paint them, throw on 20-22-24" rims, clean them up, and sell them for $6000-$8000 each. Who cares how many miles are on the car when it's rolling on big boy rims with a candy paint job, right?