Had an oddball couple in who were initially looking for "Hungarian artists" and eventually checked out with a stack of books from the dollar cart. I had this exchange with the gal.
"So, how much are encylopedia sets worth?"
"Well, we don't deal in them."
"Okay, but how much are they worth?"
"The aren't salable these days, not much demand for them."
"Oh, but there will be. Wait until next year, then EVERYBODY will want them!"
"MMmmmmm. Have a nice day!"
Hear that Brittanica? You should have stuck it out a while longer!