I took my first quilting class at JoAnn's about three years ago. I don't remember how much it cost but I'm guessing $35. They offer beginning sewing too. If you watch the sales they have offers of classes for half price. Do you get an allowance or babysit? You could save up money from that. Does your school offer sewing? At 13 you're probably in 7th or 8th grade so they may not. Do you know the art teacher at your school? He/she might be able to help out. I gave a machine to Goodwill a couple of years ago. My husband had bought it at Target for about $80 and I quickly outgrew it.
You are a perfect example of how sad it is that they don't teach sewing in school anymore.