"Dynamic pricing essentially is pricing things different for different people at different times, for the same product," said John Simpson of consumerwatchdog.org. "So you start to have the ability of really discriminatory pricing."
Retailers track spending habits through "browser cookies," small files automatically downloaded from websites. Previous behavior could be an indicator of what someone is willing to spend: a consumer who shops at high-end retail websites may be willing to spend more than a discount shopper.
"You leave a trail. You might think you're anonymous on the Internet but you're really not. Your name may be private but your computer name is not," said UCLA Marketing expert Professor Dominique Hanssens.
Shoppers can avoid dynamic pricing by disabling third-party cookies. The option can be found in a web browser's settings. Consumers can also use one web browser for research, and another for purchasing.