Here are some options for the actual car itself. If your budget is small then the easiest and cheapest solution would be to buy a Tamiya TT01 that is RTR (includes radio, and esc).

http://www2.towerhobbies.com/cgi-bin...?&I=LXJSW1&P=7

More expensive options are the TA05 or TC4. The TC4 can also be bought as a RTR, while the TA05 would need a separate radio system, and ESC to run.

TA05 (just the kit)
http://www2.towerhobbies.com/cgi-bin...?&I=LXKSG0&P=7

TC4 RTR
http://www2.towerhobbies.com/cgi-bin...&I=LXMGP9&P=ML