The cheapest I'm seeing M193 and M855 coming up for sale on other forums is about $0.60 per round, and at that price, it seems to be selling in 500-1000 round quantities. I've seen people asking $0.80 and sometimes even up to $1 per round for the stuff, but I doubt it's selling fast (or at all) at those prices. That's up from the probably $0.40 per round that it cost originally.
I haven't seen much of the MK262 stuff selling lately, but the last stuff I saw selling in the classifieds was $1 per round. I'm guessing it was probably closer to $0.75 per round originally, but someone else here may have more expertise on this stuff.
I may be interested in some of your ammo depending on how you price it and what quantities you have.
Just out of curiosity, where are you going, and what brought on the move?