More than 100 retailers including Wal-Mart and Target as well as key trade associations are launching a new coalition aimed at fighting a Republican proposal on how imports get taxed, which they believe would harm their businesses. The National Retail Federation, along with the American International Automobile Dealers Association, the National Grocers Association and others are joining forces to form Americans for Affordable Products, which will run a campaign to educate consumers and show lawmakers that the so-called Border Adjusted Tax plan would lead to higher prices of as much as 20 percent on everyday items including clothing, food and even gas.