How can I redecorate my bedroom for little or no cost? (I am 15)?

I HATE my room. It's girly and it doesn't suit my style! My style is casual and I look hypocritical when I invite people over my house and they see a girly room. It's pink and has tinkerbell all over it.. PLEASE don't just day buy new paint, furniture, or a rug, because my parents refuse too! I know I can take down the tinkerbell, but then what can I put up? Any ideas? I can do crafty things but I don't know what to do. I can pretty much only get things from Joanne's fabric store.