My sister-in-law (going to be 22 soon) has been driving a used car with probably ~160,000 miles on it for the last two or three years. My MIL bought it for her for $5,000 or so, and it has had a ridiculous number of problems since she got it, including dying at a stoplight last year and again on a test drive with a shop while she was trying to get a "weird noise" fixed. SIL has taken pretty good care of the car overall, it was probably a little lemony to begin with.
The solution to this issue, obviously, was to buy a $22,000 used Crosstrek.
SIL is a full-time student and works ~15 hrs a week, giving her ~$300/mo in disposable income (not including whatever she's living off of from her loans). I'm not exactly sure how she plans on making her payments AND buying food. MIL says it will be a "life lesson" having a car loan to pay every month.
On the super-bright side, DH was completely shocked by the purchase and really tried to talk them into looking at nice used cars at dealerships or on Craigslist, and said it should be a "life lesson" that you get to drive a used car until you have, say, a real income or a full-time job. Personally I'm good with used cars forever, but we're working on it :)