Screen capture of a very expensive book.

Amazon isn’t always the bargain they’re cracked up to be. Take, for instance, the $23,698,655.93 textbook Michael Eisen, an evolutionary biologist at UC Berkeley, discovered for sale on the website. According to Eisen’s blog post:

A few weeks ago a postdoc in my lab logged on to Amazon to buy the lab an extra copy of Peter Lawrence‘s The Making of a Fly – a classic work in developmental biology that we – and most other Drosophila developmental biologists – consult regularly. The book, published in 1992, is out of print. But Amazon listed 17 copies for sale: 15 used from $35.54, and 2 new from $1,730,045.91 (+$3.99 shipping).

Sighting such an impressive anomaly, he did what any self-respecting scientist would do, he investigated:

At first I thought it was a joke – a graduate student with too much time on their hands. But there were TWO new copies for sale, each be offered for well over a million dollars. And the two sellers seemed not only legit, but fairly big time (over 8,000 and 125,000 ratings in the last year respectively). The prices looked random – suggesting they were set by a computer. But how did they get so out of whack?

Amazingly, when I reloaded the page the next day, both priced had gone UP! Each was now nearly $2.8 million. And whereas previously the prices were $400,000 apart, they were now within $5,000 of each other. Now I was intrigued, and I started to follow the page incessantly. By the end of the day the higher priced copy had gone up again. This time to $3,536,675.57. And now a pattern was emerging.

Eisen soon discovered that the two sellers’ algorithms were in a robotic price war. Each resetting its price once a day, when it “noticed” the others price change. Both, as Eisen notes, “were clearly using automatic pricing – employing algorithms that didn’t have a built-in sanity check on the prices they produced.”

When there are no humans around watching the shop the race-to-the-bottom, can just as easily become a race-to-the-top, . The glitch in this particular instance is that this particular book has not takers.