Special to the Advance PHARR — For the 12th straight year, all U. S. Walmart stores and Sam’s Club locations are launching the Fight Hunger. Spark Change. campaign, including right here in the Rio Grande Valley.The goal of the annual cause marketing campaign is to provide people facing hunger with access to the food and resources they say they need to thrive. Here is how it works: The campaign will run in stores and online from through March 31, with three ways for shoppers to participate:• By donating at check- out in stores or clubs or round up at Walmart.