I had a lousy experience once trying to help an elderly woman sell her deceased husband's customs. A buddy of mine who owns a local and credible Art Gallery called me to join him.
They were some nice older 70's folders and a Joe Kious fixed blade with a wooden scabbard. That one was probably worth, maybe $500, at best. I don't even recall the other makers, barely notable. I told her the pack was probably only worth $1000 to a dealer.
She was aghast: "No. You are wrong. My husband ONLY collected top-level knives. I searched the internet and they are so rare they aren't even mentioned." So I gave her the number of Dave Harvey at Nordic Knives to follow-up on her own. We also looked at her husband's old camera and lens collection. I found them interesting, but I knew nothing about them.
Buh bye!
A couple of weeks later I get a call from my Art dealer who tells me she ranted at Dave Harvey for conspiring with me to devalue his husband's knives, and also she is now missing a lens from his collection. She inferred I'd pocketed it.
No good deed goes unpunished! My buddy laughed at the folly.
There is a REALLY good authority on pricing a collection.
Harry Rinker. If you want a VERY knowledgeable advice on selling large lots of collectibles (read: knives) this is WELL worth the read. Parts I, II, & III.
http://www.harryrinker.com/col-1440.html
http://www.harryrinker.com/col-1442.html
http://www.harryrinker.com/col-1444.html