From airline tickets to burgers, from groceries to gig work — technology now allows companies to change prices in real time, sometimes a hundred times a day, as grocery chain REMA 1000 in Norway does. Advocates say it maximizes efficiency and sometimes even helps consumers. Critics argue it can gouge buyers and underpay workers. The concept of prices as moving targets has been polarizing, but perception and timing play important roles in determining the winners and losers of dynamic pricing. (Source: Bloomberg)