On Jan 3, 2020, at 7:39 PM, Jack Blake via cctalk <cctalk at classiccmp.org> wrote: I see the same thing all the time on Amazon and various other used booksellers, it's a malfunction of using an automated pricing system. My uncle has spent years importing college textbooks and explained it to me about fifteen years ago, the system is fairly simplistic and sets prices automatically based on other seller's prices. The sellers have no idea what anything is worth, so they trust the automated system rather than the buyer. One person comes in and prices an old manual at some randomized, arbitrary amount in the hundreds of dollars (or a computer in the thousands), and the entire market adjusts to selling at that price without any human interaction. The systems then ignore the lowball prices set by sellers who run smaller businesses and need to move inventory or sellers who understand the actual value of the item. This leads to situations where an old paperback about an obsolete programming language gets priced at $455 and a half dozen other sellers under-cut it by pennies. If you want to see how this same sort of thing affects various other markets, look into high speed trading firms.