So, decided that I needed another hefty computer science tome, this time Volume B of the Handbook of Theoretical Computer Science. Looked on Amazon.com, and found a copy in Marketplace for the very reasonable price of $35. Ordered, paid, etc.
Got a mail from the seller saying "Amazon-mandated shipping rates too low, shipping will cost more than I get from the sale, looking for cheaper options. I no longer need the book - just want someone else to have it".
Replied, pointing out that USPS Priority International costs less than his cut (the book weighs 2.5kg).
He refunded my money with a rather patronising explanation of the breakdown of his proceeds.
Pointed out that he should consider pricing his books in such a way that he doesn't lose money, and that if he doesn't want to sell internationally, he should make that clear.
He replied, asking "I wonder who you think you are".
Suggested that I was apparently someone who was under the mistaken impression that they'd just entered into a contractual agreement with a good faith seller...