I never got an allowance, and I worked harder than most adults (my parents owned a horse ranch). I didn't even have the option of taking on extra work for money from my parents, they always said if you see extra work, just get it done (so I consequently would never "see" extra work). I was very enterprising though and would find ways to make money off of my school m8s and teachers (probably why I own my own business now).
My most profitable venture was selling pornography. I had a m8 of mine who looked much older buy porn from a local discount store for dirt cheap, then I'd sell it at $10 a mag and $20 for a video to the kids at my school. The teachers were on to me, but they couldn't ever catch me doing it. The best they ever had were some kids who got caught with the magazines word that I sold them to said kids. Since they couldn't get any evidence though, they didn't punish me. Afterwards I got a bit more clever with my schemes, but they were never anything too dangerous. My worst was selling stink bombs, after a few childhood terrorist events, I stopped selling them. I didn't want to be responsible for stinking out the cafeteria.