I'll see your "lease a car" and raise you "learn the auto market, buy a car, drive it for 3/4 months and sell it at a profit." Lots and lots of people do this

I'll see your "lease a car" and raise you "learn the auto market, buy a car, drive it for 3/4 months and sell it at a profit." Lots and lots of people do this for a living; they're called "wholesalers". You can pretty easily get a wholesale dealer license (go to your local DMV if you're in the United States). Once you have this, it will allow you access to dealer-only auto auctions, and the ability to sell more than 3-4 cars a year (I forget what the law is). Granted, this is a considerable amount of work, with a pretty high risk, but it can be really profitable if you know what you're doing.