As a father with two kids in college in California, may I put my 2 cents in here?
1: $20-30,000 of debt is about average for one year of schooling these days if you go through the University of California (UC) system. That includes schools like UCLA, UC Berkeley, etc. Prices are substantially cheaper if you go through the California State University system at schools such as CSU Northridge, etc. These are state supported schools, so the tuition runs about $3200/year. Of course there are other fees such as books. Although they're not as prestigious as the UC schools, you get a great education for 1/10th the cost.
2. You MUST have a car in California. The mass transit system sucks. This means you'll have to figure on purchasing a car, insurance, gas, repairs, registration, etc. You can get an old clunker for not much money and use it for transportation.
3. ANY money you spend now is considered an investment in your future. Don't worry, you'll pay it back eventually. A person with a college degree earns on average $1 million dollars more than a high school graduate. Get the loans, grants, scholarships or do work/study...just get that education. I personally worked my way through college and had two small loans that I repaid after just a few years.
4. As far as living expenses go, $700/mo is about right. Many times you can rent a room from a family for much less, say around $350/mo and have full house privileges. It's not the coolest way to live, but definitely worth checking out. After all, it'll probably be a private house with some sort of rules. But if you can avoid the party scene, it's an economical way to go. (Lots of parties in LA, or so my kids tell me.)
Hope I didn't sound too preachy. I live in LA and went to school here, so I have some insight on the topic. Good luck.