I went into a local collectibles store, to purchase a couple DS games for my daughter. I saw a pile of coins mostly modern foreign, with two junk mercury dimes and two junk silver washingtons. I asked how much he would sell the mercs for. He suspiciously looked at me and said two bucks apiece. I mentioned that the silver value was about 1.40 each, but he told me they sell at a premium. I then asked how much for the two quarters. He said he had to go look them up online and see what they are worth. Five minutes later he returned and quoted me 1.50 each. So I ended up buying them all. I'm not sure what he did on his computer, but I doubt he checked what they were worth.
Reminds me of buying worn out SL quarters a couple of years ago at an antique store for $1 each - back when the silver value was about $5 each.