Remember there was a time before computerized inventory. A book was bought, given a price and put on a shelf. That book might go up in value. The person who priced it might not work there, or remember to re-price it among the tens of thousands of books in a store. I could buy it because I recognize it went up in value then sell it back (though to be civilized about it, not that day). Some bookstores are so large they might sell a book from their warehouse then buy it back at a profit to me over their counter. Before computerized inventory this was far from unusual or irrational. Now a computer will remember what no person could remember.
An aside: The Old Brown Coat by Lord Dunsany is a short story on this topic.
That sounds like arbitrage combined with razor thin margins and imperfect information;
Intransitive preferences are a demonstrable characteristic of human behaviour. So why am I having such trouble coming up with real-world examples of money-pumping?
"Because I'm not smart or imaginative enough" is a perfectly plausible answer, but I've been mulling this one over on-and-off for a few months now, and I haven't come up with a single example that really captures what I consider to be the salient features of the scenario: a tangled hierarchy of preferences, and exploitation of that tangled hierarchy by an agent who cyclically trades the objects in that hierarchy, generating trade surplus on each transaction.
It's possible that I am in fact thinking about money-pumping all wrong. All the nearly-but-not-quite examples I came up with (amongst which were bank overdraft fees, Weight Watchers, and exploitation of addiction) had the characteristics of looking like swindles or the result of personal failings, but from the inside, money-pumping must presumably feel like a series of gratifying transactions. We would want any cases of money-pumping we were vulnerable to.
At the moment, I have the following hypotheses for the poverty of real-world money-pumping cases:
Does anyone have anything to add, or any good/arguable cases of real-world money-pumping?