WHILE we are talking about great businesses.. one that is soo untapped it's unreal, is doing the same thing for cars.
I found that out by accident. My "patch in car", the car I got right when we got a little successful, just so I can have something to get around in, but nothing too expensive, was a 1993 Lexus SC 3000. I paid I believe 2900 for it, the guy had just bought a new car and didn't have a use for it anymore.
When I got it, the only thing wrong with it was it needed some freeon and some power steering fluid. I replaced the CV joint, myself, for I think 110 dollars just for good measure. So all in all you are looking at like 3200 dollars for the car.
About 9 months later, when it was time for me to upgrade, I put it in the paper, and sold it for 5200K, with a CD player that needed replacing!.. they basically just paid for it because it was a lexus. Even had 180k miles on it. I mean, it was clean as hell and has no problems with it, but I was suprised I got that much for it. I was going to sell it for 3k, and my business partner convinced me to put in in the paper for 5500 saying "what's the worse that can happen?".. And the guy though he was really doing something talking me down 300 dollars.
I bought my Ex GF a car when we were together. She basically lived with me, and I didn't like her driving my car, because well.. it's my car, so I got her a 1996 camary, just to get around in .
When she split, or when I booted her, I sold the car the next week and made about 700 off of what I originally paid for it, and I didn't put any work in it.
There was a guy at my old apartment complex that did that for a living, and he was my age driving a Range Rover, so he was doing pretty well for himself