I'm trying to write 38,000 more words on Ten Gentle Opportunities (basically, the rest of it) by Worldcon, so I won't go on at length about this, but today I stumbled on some information on a topic I mentioned briefly several years ago: The weird way used book prices wobbulate around on Amazon. As it happens, the goofuses are apparently using software originally developed for high-speed stock trading. Techdirt explained the process in a little more detail last year, providing us (finally) a clue as to how a mild-mannered book on the genetics of certain flies could come to command the super price of $23,698,655.93. Lots more out there if you're interested.
In short: If you define your book's price as 1.270589 times that of your competitor's, and your competitor defines his price as 1.270589 times yours, well, you'll both be rich in no time...or at least pricing your books as though you were. Fly genetics never had it so good.
What remains a bit of a mystery is why you'd want to price your books above your competitor's and not below. Unless...the game is to buy the book from your competitor when you find a buyer so dumb as to buy the book from you, at 1.270589 times the price they could get it elsewhere. It's likely that the fly genetics book was not in either seller's hands at any point.
Such clueless buyers may exist--after all, people are still installing smileys and comet cursors and anything else on the Internet labeled "free." This implies that the magic number 1.270589 is in fact the atomic weight of Sleazium, which absorbs certain subatomic particles, particularly morons, better than anything else ever discovered.