The experimental methodology used by Amazon to determine the optimal price is standard and is widely used both in online and offline settings. Consumers are randomly offered different prices. Then the retailer collects sales data to determine which price performs best. The problem for Amazon was that the giant is both large and online where consumers can easily share information. Consumer got together and learned they paid difference prices for the same DVD on the same day. For example, the E-commerce Times reported that when they checked the price for the DVD Mission Impossible it was $17.99, but several hours later the price was $20.99.