Chances are, whatever they're building doesn't need to be put in private repositories. If it really does (as in, they're working on commercial stuff), $7 a month (even $12) shouldn't be hard to scrounge up, and I'm an in-the-red student myself. After all, we all need to learn about business expenses sometime--and they're not having to worry about paying for food or rent. If a private repo is that important to them, most schools offer private server space. I say no.