Shot glasses....if any are really old or unique maybe eBay might make you few dollars. (or etsy if vintage) One from a hotel in Cuba or from an original Vegas hotel shot glass might sell. Tanqeirs hotel stuff sells well.
Otherwise your looking at 25cent table filler at flee market IMO.
The last two lkrs I bought EACH had shot glass collections. One had about 75, the other maybe 30. I have been putting about 20 or so at a time on one of my tables and sell them at $2 each or 3 for $5. The collectors will pay that much (in my experience) if they find one or two they like. I have also had people walk away at that price. I think they go for $3 and up at stores, so not a reach for me to sell them at $2.
After all, how many places will you find "just the one you've been looking for" unless you GO to that spot 3 states away?
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I used to do well with DVDS, but anymore I try to sell them for $3 each and 2 for $5, but sometimes go for $2 each straight up. HOWEVER, the movie business is a TITLE DRIVEN business. If someone finds a title they want, they'll usually pay for it. If they balk I remind them that they could look all day or drive to 3 or 4 flea markets and not find it again. This usually works, but not always.