How much money should I set aside?

I'm very heavily considering buying a PA system for my band which may or may not take off. I'm not relying on our success at all, I just want to have a great time. The most I'll spend on that is $1,500 to get a nice starting point and sound good. However, that's pretty damn close to all my money. I'm a junior in high school and 16 and wondering how much money I should keep set aside for emergencies and the like. The only monthly expense I really have is gas, but I don't drive a lot, and it costs like $20 to fill the tank and that lasts me about a month. I definitely plan to attend college, if that matters. I'll probably just get a job while in college to pay for food and other things I may need while I'm there. What I'm trying to say is that I'm skeptical about such a large purchase and would like some financial advice on the whole situation. Thanks for reading and stay happy!