Being a waitress through college was what kept me eligible for financial aid. Waitresses make crap on paper, and you take home all the cash you make. My taxes are paid by the 2.13 an hour, and I usually get a nice refund in April. I had to keep this job because my wages were being garnished for certain reasons, but I was still able to pay my bills in cash and go to school. I didn't have a bank account for 2 years, but my wages as a waitress couldn't be garnished because what the company paid me was less than 25% of my income. Seriously, I've been working in restaurants for 10 years, and most of the people that keep those jobs are in situations like yours where they need to keep the money they make and not hand it over to someone else. And most restaurant managers understand that too.
I think your main problem is paying 500 bucks a credit hour to go to school. I got one degree from a state school and I am now going back to a jr college to save money. It costs me 650 a semester to take 12 credit hours, 1300 bucks a year! Those classes are the same on paper, and you only have to take the last 60 hours from the college where you want to receive your degree. With one degree under my belt and two more on the way, I can't tell you how much this advice would have helped me out 7 years ago.
If it makes you feel any better, people are struggling for money all over the country, and the cost of education just keeps going up. You aren't alone.