lets seee, you want at least 180mm fork travel, triple clamp will help the serious and pro riders but its up to you, you want a frame with at least 6' of travel, a fairly new or well maintained drivetrain, also look for fork and shock service historys. unless you get a run down old bike for +- 4k and then fix it up. for example I bought a Scott Nitrous 30 for about 6k and now im slowly building it up, just got new cranks put on and it looks awesome, and sometimes you get lucky with the older (cheaper) bikes, but like Panik said, show us what bike your interested and we will help you out and give you some advice
