Asklemmy

Kind of a "duh" thing but, only buy used cars.

Always have a trusted mechanic who doesn't work for the dealer look it over before you buy. Usually new car dealerships are reputable and are looking to move their trade-in inventory, especially at the end of the year when they need to clear the lot for the next year's models. You can even find deals on vehicles that are only a year or two old like a returned lease, with a moderate number of miles on them and little to no wear and tear. Those are usually just as good as new but so much cheaper.

Be super cautious of the used car dealer chains, like Drivetime and Carvana, they have loads of customer complaints and legal problems in a couple of states (basically, if it seems too good to be true, it is). Do not ever buy a former rental car, unless it's true love at first sight or you're desperate... even then think about how people, who've only paid like $10-20 for rental insurance, have probably treated that vehicle and reconsider.

The newest and most expensive car I ever bought was a previous model year's dealer demo. A dealer demo is what it sounds like, it's the car the dealership displayed in the show room, used for test drives with unsure buyers, running office errands, and showing off at the mall or in parades. Cons: There's only a few of them, they'll have a couple hundred miles on the odometer, and you don't get to pick the color or options. Pros: They're usually at a decent trim level, in an agreeable color, and well maintained... for thousands less than brand new because they've already left the lot a whole bunch.