I have a car! I went to the Toyota dealership today, and set up the appointment through the Costco auto program, and I had an amazing experience. It did take an absurdly long time (I was there from 9:30-2:30), but that was 90% my fault, because I had to figure out insurance and talk to my parents about all of my options (because they're helping me out with payments). It was a bit more expensive than I would have liked, but that is only because I had no idea how freaking expensive car insurance is in California. I knew it would be more expensive than my previous Minnesota plan, but it was way waaaaaaaay more expensive. The car itself I actually got for a significantly better price than I expected, so I'm very happy with that. I'm definitely going to have much less money for extra stuff, but I'll be able to manage it. And now I can drive to places! I'm still planning on commuting primarily by train, which is good because I am currently terrified to drive my new car, but having a car in LA, even when you're lucky enough to have some public transportation options, makes a huge difference.
Anyways, thanks to everyone for all of your advice and encouragement when I was insanely stressed out by the last dealerships. The Honda people are still totally getting a bad Yelp review, but I'm a little more calm now.