Title says it all. Seventeen year old looking to hold onto his funds. I already read. I lift 6 times a week and I've been making extraordinary gains.

I need something to fill my summer days. My college schedule next year only has me in school two days out of the seven, so I need something to work on and practice. I'd like something that costs little to no money, since I'm trying to save my funds and my parents are a little stingy with their cash. They keep me fed and give a roof, so I don't mind supporting my own hobby as long as it's cheap.

Any recommendations?