OK, I'll stick my neck out...
You going back tomorrow???
Look for 110's with square edges; not rounded...look for 2 brass rivets + one steel rivet...make sure the blades aren't scratched up a lot...if you see a black "handled" 110, with what looks like cloth in it, it's a good one...worth a bunch...if you see any 110's with only one line of text on the blade tang, or two lines, they're worth buying...if they say "Custom" on them, they're worth buying...if they say "BG-42", "ATS-34", or "S30V" on the blade, they're worth buying...
For anything I listed above, I wouldn't pay more than $60...but that's just me, and they'd need to be in great shape...not all bunged up, or ground down...
Oh - take a pocket ruler with you...don't buy any 110's less than 3 5/8" exposed blade length...3 3/4" is ideal...
Hmmm...What else???