In the latest phase of the desperate race to survive against Amazon's immense selling power, brick and mortar stores are increasingly aping one of the retail giant's most potent practices: dynamic pricing.

Between the lines: This increasingly popular tactic — in which a seller constantly adjusts the price of its products, for example hiking hotel prices during a big convention — benefits both buyers and sellers, its defenders argue. But as pricing is increasingly automated, the dangers include gouging and discrimination.