I forget, is that a typical smaller bladed finishing disk, or a real brute of a heavy duty tillage disk? Can't remember my ihc model numbers....
I think $500 is a good starting point for a nice finishing disk, a disk with worn blades is worth so much a lb scrap iron, and in a more suburban 10 acre farmstead area could be worth $1500.
I'm in southern mn too. Don't see so many that small any more so,if you want one, hard to,pass up.... lot got scrapped the last time iron prices went up.