i went throught the exact same thing a couple years ago....im 15 now and i race at a local club, gas cat. if i were you id start out with whatever you can find used for cheap. if you wanna build, you could do what i did the first time...build your own small mono/catamaran using plans and buy the stuff you need used. ive got a strut, prop, rudder, and .18 pullstart engine, manifold, pipe, seein that i was in the same position a while ago id definitly sell it to you very cheap....also have the plans to a sweet little cat im building right now designed by Eric Perez i could send you if its okay with him.
the only down side to that is if you've never built anything small from plywood before and never driven anything nitro rc it would be very hard to get it working well without any help, but if there's someone in your area (which there probly is) they could help you, and the guys on here are all great, and DEFINITLY know what theyre talkin about.
badminton? durn the west coast is different.....then again yall probly dont have lacrosse.
btw are you a niners fan?
Joe