Getty Images Usually when companies fight each other, it's consumers who get the worst of it. But right now, we're witnessing a business battle that's actually benefiting consumers in a big way. In this corner: Amazon (AMZN). In that corner: Overstock.com. At stake: Which site gets to claim it has the lowest prices on books. For years, Amazon has had sole possession of those bragging rights. But Overstock, a discounter not as widely known for its book offerings, is trying to make a splash in the book game by beating Amazon on price. Starting July 22, the site began offering to match Amazon's prices on hundreds of thousands of books, and then lower the price by another 10 percent. Overstock is applying the program to 360,000 of its titles. Not to be outdone, Amazon is going through its list and discounting its books to beat those prices -- which is causing Overstock's computers to respond by lowering their own prices again. The result is a race to the bottom, with the book-buying public realizing huge discounts on even the most popular books. Gillian Flynn's "Gone Girl," for instance, is a bestseller that came out in June and has a list price of $25. It's currently $12.84 at Amazon, but Overstock has it for just $10.63. The Amazon price history of the book shows that the price started dipping shortly after Overstock's price-match program went into effect. The price war is largely being fought by the two e-tailers' computers, which are programmed to periodically check the competition's prices and beat them. While algorithms of this sort have gone a little screwy in the past -- consider the case of the biology textbook that wound up priced at $23 million -- we're guessing there a fail-safes in place here to make sure the prices don't go too low. That's probably why we aren't seeing books selling for pennies on either site right now, and likely won't. Still, Overstock pledged Thursday that it would keep up the promotion for at least another week. So if there's a book you're looking to buy, now is the time to do it. Check the prices on both sites, see where you're getting the better shipping deal, and then click "buy" before the two companies declare a cease-fire.