hey dude, i say give it a shot, they'll probbly have you emptying trash cans, and doing junk, rather than nails. my cuz, used to work in a joint like that, and the girl's who mainly do the nails, love having a gofer around. Go fer coffe, go for another 5 gallon bucket of cancer causing stuff. Hope the joint has ventilation systems above the stations, and go for it. But if they actually want you for painting nails, they must be desprate, or you've exhibited some aptitude to dextrous tasks.
And 900 a month, ain't too bad. Of course for after school work, if you really want to learn pc's find a friend of the family that works at a small office, that doesn't have any IT help.
I learned alot that way, because at my dad's office they have about 30 pc's but no IT in the office, and my dad used to cover it on his weekends, but they've gotten more pc's in the office, and more idiots working them, so very frequently, I found myself in there helping, and I've been able to learn alot.