I know I have a matched pair (close serial numbers) of K77's at my shop, and may have a pair of M's as well. I semi-regularly get $279.99 plus shipping on eBay, but would sell a pair here for $239 shipped to the U.S, paid via Zelle or PayPal F&F. If you wait around long enough, a more reasonable pair will show up here on the forum, but if you need them now, I can do that.
Jeff