I am a university/college student and do web design and coding whenever I get chance, it pays a lot better than most of my mates get for stacking shelves or pulling pints so I'm happy.
I think a lot of people on DP would be students because web design is a great way to make money when you are a student, all that time on your hands and supported through your parents or student loans, its a great time to get established.
I run two companies.... one is simply myself as a project management/ business consultant and the other is Astaroth Solutions - time split is probably about 50/50 but consulancy tends to be more office hours in the week and AS more evening (lots of USA based clients) and weekends
Part time doing legal assistance day time and online direct marketing in the evening also part time. Totally it makes full time and brings pretty good income
Another University student here - I'm a lazy arse, so no other jobs apart from the online biz (and I barely do that, too )
I'm a student with a part-time job, I make more online per week that I do with any part time job, I should really quit but I know that my part time job is going to pay me aslong as I do something