Everything is negotiable. The questions are how bad do they want rid of it, how much is still sitting and how long have they been looking at it wishing some one would haul it off.
If you let it sit, someone may take it. If they don't, the price drops. I have walked off after having a manager tell me "it is a good deal". Not good enough. Your loss or my money.
I bought 10 of those fiskar hand cultivators from Walmart. Originally $7. Too many left at the end of the season, now $1.50. One for each flower bed and I can usually FIND one when I want it. Best $15 I spent at Walmart in awhile.
Goodwill is more take it or leave it. We discount in 4 weeks. See you then. If it is obviously overpriced, they may work with you. The manager I got to know left, the new one is inflexible and prices it at new value. The good deals have left.
Pawn shops are like what I imagine bazaars are. Everything is negotiable. Before the internet, local markets ruled. Now, check ebay. That is the price. Bigger ones have corporate pricing the merchandise. Not as much fun. I can imagine NYboy has stories about antiques.
Oh, poorer sections or smaller cities have better pricing because of the smaller customer base. Less quality though everything varies.