They generally won't cover housing and food costs to make up for the lost wages while going to school, especially if you have a family to feed. One might make it working part-time so long as you have a spouse to help you out. But hey, folks get lucky. Others don't, though, and still wind up paying for some books and fees on top of taking out loans. Not to mention buying things like a current computer, making sure to have internet access (lets face it, with a job, kids, and school, you probably aren't making it to the library), and so on.
Afterwards, you'll need to pay that student loan back. You get 6 months before you start paying it back. You might not even find a decent job at all.
There are income-based payment plans. They require not falling behind on your loans most times, and even if they don't the private company collecting might make you think that way. If you can't pay and stupid things happen, they'll garnish your wages. 25% (ish), but they'll make sure to leave you a salary equal to 30 hours work at minimum wage. They'll take your tax returns too.
And as an odd fact: It really ins't possible to take out loans for part-time schooling if you want to get a bachelors degree: Federal student loan funding stops after 6 years, at which point you must pay off the first year's loan to get another year. (I think full time does 5 years). You might be able to get an associates or professional certificate at the local community college, though, if you are lucky enough to have one in your area (many do not).
I know this isn't everyone's story, but this stuff is common enough to consider as a risk factor. It might have been a way to financial stability at one time, but it isn't such a sure thing anymore.