To me I'd prefer to buy a new one. Abernathys in Tenn is selling them for like 16500 brand new. But depending on who built the cage and such that sounds like the normal going price.
I wouldn't spend that on a used one either, that they sell for that much. The 2 I've bought were new just bc I wouldn't wanna buy one that's a YouTube hero
It would depend to me on if you were buying or trading. I'll always allow a little more in a trade than I typically think something is worth but I make sure I get my asking price. You always gotta have wiggle room.
As far as the rzr, I don't think you will ever sell it for that but if you want it to ride it may be "worth" it.