I would say if you're serious about your budget then you should start looking used. There are lots of great deals out there on MBX5R's, RC8's, 8ight 1.0's and HB D8's all of which are more than capable of winning at the club level. There's a Go Tech 3 port with 3/4 of gallon through it for $90 in the FS forum right now. Look around, and most used cars also come with at least some spares which you'll need for racing.
Good Luck!