How can a 14 year old girl make $300 bucks easily?

I want to save up to buy the 3ds. I already have the dsi with a few games, but I don't like selling my stuff. What should I do? I don't want to ask my parents for it because they are already going to buy me back to school clothes, pay band fees, school supplies, pay for my braces( monthly), rent me an instrument for band for like 30 or 20 bucks. But then again I'm the only one they waste money on now that my siblings are adults. But also they have to pay this $250 tickert for parking in front of a fire hydrant