Make Pretty Jewelry for Cheap?

I'm 17, and super bored. I wanted to do some type of craft, and I thought I could make jewelry. But, I don't wanna make the baby kid stuff, I wanna make something that looks good, and stylish, and possibly something I could sell for cheap. I don't know where to start, what to buy, or how to make jewelry. Any tips? Websites? I'm really interested in making the jewelry and possibly selling it too, but I also have a tight (and small) budget. All help is appreciated! :)