Today begins CKE Restaurants “money back guarantee” for anyone who buys its Six Dollar Burger at Carl’s Jr. or a Thickburger at Hardee’s. The two chains will give customers a refund if they think that the McDonald’s Angus Third Burgers are better than any of Carl’s Jr.’s Six Dollar Burgers, or Hardee’s Thickburgers. The offer is valid until Oct. 13th.