Check ebay out, lots of good deals on buggies. I picked up my brothers sp2 for 200 and my sons for 250, just rollers with my sons being upgraded with lots of king heads parts and only ran 3-4 times. It looked new with only 2 small scratches on the lower plate. Im not saying get a kyosho, or losi or mugen, thats your choice. Check your hobby shop for parts and go with the brand they carry parts for.
Roller for 200 leaves plenty to build a nice entry level buggy.