I've seen the same trends in junk shops.

I blame the internet and more specifically ebay. Nowadays a lot of the shop owners look up absolutely everything that crosses their doors on sites like ebay to see what they could possibly get if the auction goes perfectly.

People also scour junk shops looking for things to sell on ebay and the shop owners are aware of it.

Really, in these instances, about the best thing you can do is try and haggle the price down.

If the seller brings up ebay prices, tell them that they're not going to get as many people that want the item walking through the door as would see it on ebay. If they then say that they might as well list it on ebay, tell them that they should.

These people also have to pay rent, electricity and so on, may look for a quick sale and may be more willing to haggle than you might think.