The internet is a useful tool
Here's my opinion, take it for what it's worth.
I like to stop at garage sales, estate sales, auctions and whatever type of sale I come across that I think may be worth at least taking a look.
A) Last year I went to a local swimming pool and spa dealer that had acquired billiard supplies (he placed an ad on Craigslist), and wanted to get rid of them. He was offering deeply discounted prices on house cues, balls, tables, etc. Some of the stuff was junk, but I picked up an unopened set of Aramith balls for $40, a gross of Master chalk for $7, and three cheapo house cues for $2 each.
B) I was cruising the flea market and found an old Dufferin. Straight, good tip, and with that weird joint pin. The old man wanted $2. I bought it, and sold it online for $47.
C) One garage sale, the owner was selling a non-slate pool table, with about 6 cues, for $25. There was an old two piece Adams in the bundle of house cues. As I had no use for the table, I negotiated for the cues. The entire bundle for $5. I paid, and as I began to walk away, the owner said, "Wait, I gotta have a cue to sell with the table". He grabbed the crappiest cue, and I left with the Adams and the remaining house sticks. Sold the Adams online for $83.
The spa dealer ? I'd like to believe there was a computer on the premises.
The guy at the flea market ? He was on his laptop when I strolled up.
The garage sale ? The owner was on his laptop at the time as well.
Maybe back in the days, I may have been more inclined to say to any of them, "Hey, do you know what you have here ?" But with the internet, and being able to get information for just about anything, it's not up to me to tell someone what something is worth. Frankly, it's laziness if the seller doesn't want to do thier research.
Anyone ever see the Pawn Stars where a guy came in with an old ham radio (or something similar to that) ? Rick looked it over, asked what the guy wanted, and the guy told him $80. Rick agreed to the price, and in the mini interview, Rick stated that "This guy did his homework, he knows what it's worth, and he's asking a fair price".
They even tell sellers that they are in business to make money (in case these people don't understand the concept).
Even better are the items they bring the expert in for. The expert looks it over, tells the owner that it could fetch $36-$42k, and when Rick asks how much they want to sell it for, the real smug ones say, "He said $36k, so I'll take that." So Rick explains (again) that they are in business to MAKE money, and offers $12k. The owner says he'll take $35k. Back and forth, and the owner relents to Rick's 'final offer' of $18k.
If the owner of the item was willing to take the time to list it in a more mainstream market online (or possibly with an auction house), he could have made even more money.
It's called "seller's remorse". Sell something for a low price, then kick yourself in the caboose for taking the low offer.
If you don't like the price they offer, the answer is easy. Walk away.