rcmart is a good place, but you need to be careful since not all there buggies comes equipped like they do in europe or us.

Other good places are www.amainhobbies.com or www.bmainhobbies.com in usa

In UK there are www.benracing.co.uk and propably a lot more that I don't know.

Good buggyes could be:

Hyper 8
Xray XB8R
Jammin X1-CR Pro

A Go 7 port is not the best engine for a beginner.

Another advice is to stay away from used stuff.