 The phone you use, the computer you own, the zip code you live in, these can all be factors in the price you see when you're searching for items on the internet. Welcome to the world of mass customization. For example, you probably know that logging on on different days and times can give you different prices for airline flights. But you might not know that Amazon can change its prices for everything from dustpans to televisions every 15 minutes, even more often than airlines. Researchers have tried to study this phenomenon, but the world of ever-changing prices is a black box that is difficult to test. Even so, here are some findings. Orbitz was found to be showing higher priced hotels to Mac users than PC users. Staples was found to sell most everything on its website, from staplers to duct tape at different prices and different zip codes. The zip codes being charged higher prices were more likely to be low income. Princeton Review charges different prices for its online SAT tutoring in different zip codes. We found that Asians were almost twice as likely to be offered a higher price than non-Asians. In the European Union, variable pricing is regulated. In the United States, it's legal to sell the same product to different people for different prices. In the US, mass customization can mean mass discrimination.