When Maria Diep opened a new convenience store in Muskogee County, Oklahoma, she though she could stir up some business by knocking a nickel off the price of gasoline. She did. She also stirred up the interest of the district attorney's office, which told her to raise the price of gasoline, or else. Under a 1949 law, Oklahoma retailers must sell the products for at least 6% more than they paid for them. The DA's office said it received several calls about Diep's store and another convenience store that were selling gasoline below the prices charged by other stores in the area. Presumably, those calls were not from consumers.