In the era of Big Data and sophisticated algorithms, major retailers such as Amazon (AMZN), Target (TGT), and Wal-Mart (WMT) keep pushing for a pricing edge. The gamesmanship includes changing prices hourly and undercutting heavily promoted deals from rivals by cents. But the biggest winner of all may be consumers. Tracking data over the holiday shopping rush shows a higher sell-through rate on items where retailers give up the most margins as mobile-empowered shoppers see through false markdowns. On watch: A potential casualty of the trend of real-time pricing could be dollar and bargain stores.