But if analysts aren't sure about the scope of the phenomenon, the tech guys building the pricing systems certainly are. One computer scientist who builds smart sites for online retailers—with a nondisclosure agreement, hence the anonymity—says that concerns about different customers getting different price quotes for the same good are probably overblown. Some retailers do it, particularly when gauging the market for certain items. But companies know that consumers watch for it, and will take their business elsewhere if they think they're getting a raw deal.
That said, major retailers are getting much more sophisticated and subtle about ways to game their shoppers. It's common for big retail Web sites to direct different users to different deals, offers, or items based on their purchase histories or cookies. They also alter their Web pages with internal ads, letting a shopper's cookies or browser data influence which sale products pop up. And companies frequently offer special deals for customers with a few items in their shopping bags—from discounts on additional items, to free shipping, to coupons for future purchases. Ingenuity, rather than price-tampering, is now the name of the game.
And as much as retailers try to foil bargain shoppers, consumers actually do hold the upper hand online. Dynamic pricing is easy to counteract. Search multiple sites—including ones that collect prices from across the Internet as well as the sites themselves. Run searches on more than one browser, including one which you have erased cookies. Leave items in a shopping cart for a few days, to gin up discount offers. And be prepared.