During most of my undergrad, the default scholarships almost completely covered me. Had to take out a subsidized loan once or twice though, but those are through the school and guaranteed. I attended a private university, so the cost of attendance was ridiculous, but they offered all kinds of random grants and whatnot to people just coming in. I think by the third year the cost of tuition went above the free money they were giving me, so that's when I checked the "yes" box for a loan. If you go to a state school, freaking forget it. You can probably work at McDonalds and pay for that. A word of warning though: at least in private schools, if you screw up and let your GPA drop too much, you are DICKED. They pull all your funding and you have to get student loans from a bank. A lot of people I know are leaving school with close to $100k debt.
Once you get to graduate school, you can get a T/A or you can join a research project. Both of those pay for tuition and (just barely) rent/food and they are fairly easy to get into. I was a T/A during my first semester of grad school, which I really liked, but it was a lot of work. Then I got pulled into a research project, which was way more laid back and still paid the same. If you want to have any kind of fun at all though, you need to have a part time job. Or save up during summer.