I got a line on a used MKIII that's supposed to be 90%.  I've not seen it and not too interested myself since the guy was talking $1000.00.

I paid $400 for mine about 15 years ago, it's got some wear and was offered 600 for mine some time back. I sold one and still regret it so this one stays but what are prices nowadays for used MK IIIs in the 90% range?

I've looked online but not finding or looking in the right place.

$1000 is pretty much the going rate for a good HiPower since FN stopped manufacture of the originals. That price might come down some with other manufacturers taking up some of the slack with lower priced examples.