I'm only a teen and live with my family. I more or less hang on what I get for my birthday, Christmas and Easter (yes, I get money instead of chocolates)
Sometimes I fall back on a money stash I have, which is added to everytime I get paid for writting out the answers to an exam, doing some assement task or something or other for other students at school, sometimes I'll tutor them for a test too.
Even selling a few guppies, decorations and pond weed for a couple dollars adds to it.
But, on the occassion, I'll fall back on my parents good will and my good grades help push things in my favour.
I'm out for a job now too, so that'll be adding to things soon aswell.