Theres nothing wrong with second hand as long as your careful and are ready to strip and rebuild. You will learn quite a bit in the process as well.
The same rules still apply, and in terms of spares doubly so.
Some projects I buy second hand because I know i'll strip it and junk half of it anyway and replace with better parts.
Look at spares availability both online and in your LHS, then go buy one of those.
I would avoid the cheaper 'copy' buggies though, as they never share 100% parts interchangeability (is that a word? I think so). Hobao, jammin, x-ray Mugen, Kyosho (but not their 7.5 RTR models), losi, AE, thundertiger (EB4S3) and some people even say CEN have their act together these days
Choose from these, buy a current model (not an older one thats ceased production) and double check those spares availability and you should be OK