Buying used karts is usually the first thing people think of when wanting more karts. And why not? It's cheaper, and you can find some great deals.
General tips for buying used:
Buying used can be an easy cheap way to get into the sport. So that's definitely a plus. But there is also the chance of getting a bad deal.
The chances of getting a bad deal go up with new kart racers. Your relatively new and you don't know everything about it yet. It would be easy to buy something that isn't in race condition or be lied to about it.
A good way as a beginner is simply find a trustful person that has been racing for a while. A good friend goes a long way in helping you get started in racing and finding quality used stuff.
You know what you need, and you know everything about it.
A Used Kart
Buying used may be the right way for you. Or you could be raking in so much money from sponsors and winnings you would just go buy new. (I envy you if that is the case!)
Still, you should do some research, ask around as you should have plenty of friends in karting. You probably know best who to deal with and who to trust around your area.
Buying used, anything could be coming with it. The seller could be doing a everything must go and trying to sell you the whole racing shop. Or he could just be selling you a bare kart chassis with nothing on it.
This depends on very many factors that I couldn't possibly all cover here. Basic selling principles come into play here. The demand, supply, and how bad the guy(or lady) wants to sell it.
You can find them anywhere. Here are some places where they show up:
Do your research, find a trustworthy partner, and take your time. Patience is a virtue.