By pairing a price increase with the introduction of a previously unadvertised “list price” for a product, Amazon signals to shoppers that they are receiving a discount when they actually pay 23% more, on average, for their new vacuum than they would have just a day earlier.You actually paid a higher price than before the seller displayed the discount claim,” says Jinhong Xie, a professor in the Warrington College of Business at the University of Florida.Xie and colleagues followed more than 1,700 vacuums and gathered nearly half a million individual observations of prices.“We found that by increasing the price by 23% on average, the seller achieves an 11% advantage in their sales rank among all products in the home and kitchen category,” Xie says.“This allows firms to achieve the impossible: increasing margins and increasing sales simultaneously.”Other products used this practice anywhere from 3% of the time for books to more than 13% of the time for blenders, digital cameras, and drones."