By Arriana McLymore and Siddharth Cavale NEW YORK (Reuters) – Target Corp is preparing to let shoppers use food stamps to pay for online orders, following in the footsteps of Walmart Inc and Amazon.com, in a move that could help the nation’s seventh-largest retailer gain market share among lower-income shoppers. Roughly 21.7 million U.S. households use food stamps, which are mostly restricted payments to cold food items, non-alcoholic beverages and seeds and plants. Target disclosed to Reuters last week that it will begin to accept payment online with food stamps, tentatively starting in late …