What to consider/look out for when buying used?

Hello folks, I have some money burnin a hole in my pocket and the world of drones has attracted my interest. I have been looking at a few on Craigslist but not knowing anything of this hobby I could see where I may get taken for a ride if I'm not careful. Also, if I was gonna go new, is a decent rig available for 5-600 bucks? via /r/drones https://ift.tt/2PBPAbX