A growing number of multichannel retailers including Target, Best Buy, Wal-Mart and Toys R Us are offering to meet rivals' lower prices on popular gifts this holiday season, driven in large part by the mobile technology that lets shoppers do real-time price comparisons, writes Shop.org's Artemis Berry. In addition to matching competitors' prices, some are also adjusting in-store prices to match their own online prices in an effort to meet customer expectations.