Are you looking for a kit, or a RTR?
If you want a RTR, the T4 (rc10t4rtr rs) is one of the best race trucks, and you can get it for $240 +/- a little depending on where you go.
The HPI is ok, but really it doesn't make that good of a race truck, and then the Losi xxx-t rtr sport 2 is way out of your budget.
Keep in mind you will also need a few batteries (2 to 4 when starting out if using Ni-Mh (I use to race with 2 packs when I first started), other wise if you go li-po you only need 1 or 2), and a charger to charge your packs. You might also want to get set of rear wheels, and the tires they are running at the track
Now if you were thinking about getting in the slash class then that would be the cheepest way to go, but only go that way if there is a slash spec class to race in.