There's several solid platforms to choose from.
Xray XT8
Mugen MBX6T
Hot Bodies D8T
Associated RC8T
Losi 8.0T
and several more, go with what you like best.
Price ranges heavily for a full setup, it all depends on what you want and how far you want to take it. It's easily possibly to build a capable truggy for half of what you could spend with high end components. You don't need to spend $500 on a motor. There's several in the $200 range that are more than fast enough. You don't need a $400 radio either. Get a solid kit and don't skimp on servos.