“Amazon accounts for nearly 40 percent of e-commerce sales in the US today, and it takes a cut of even more online shopping by selling payments services and other technologies to external shopping sites. Now, the online retail giant is making a play to grab a piece of brick-and-mortar shopping, too — and it wants customers to literally lend a hand to do it.” Amazon will now let you pay with your palm in its stores. And, it hopes, at other retailers’ stores in the future. (At least it won’t cost you an arm and a leg.)