Lower economic strata doesn't take on debt, they get aid and free rides, cherry work study jobs to put some money in the pocket too. It is the middle class or upper middle class that insists in eschewing their state school benefit for a more or less comparable school in another state (or without favorable scholarship and aid package) that take the brunt of the loans.
Work study jobs vary a lot. Some of them are just wiping whiteboards after the lecture ends in the 300 person classrooms or walking around the library taking headcount every 30 mins. Front desk shifts at the dorm were also another easy one; hand over a package every now and then just do homework or slack off otherwise. Other ones probably work you like a dog and it isn't clear to be fair what the best ones might be as far as working in homework at the same time unless you get an upperclassman to tell you.
I sure had to. Work study sure was nicer than the crap jobs I'd had but no cake walk: I graded a lot of homework and exams as well as helping a lot of rich kids ace their class.
[edit: I should admit that it's been 20 years, things may have shifted a lot]