Check your local track and see what classes or what the others are driving. It's more fun that way, even for bashing...
Starting off if you look at a RTR like a Slash it's gonna run you about $500.
What you need:
Truck RTR (everything but batteries)
2 4000 nimh batteries to start
Set of standard tools (some come with the kit)
Battery Charger
If you go with a kit, it's going to cost about 200-300 more for
motor
ESC
Controller and Receiver
Sometimes on rctech you can find a used truck for great prices as well as ebay.