Hey, Im build a mountain bike. I want it to be as light as resonably possible. I'm looking to save some money by either buying the whole bike used or just the frame. I want the frame weight to be also very light. I dont want to spend over 300 bucks for a used frame. Throw as many ideas at me as you can. Tell me the frame weight if you know it. It also need to have braze ons for a rack in the rear.