The Federal Trade Commission and 22 states sued Amazon on Monday, claiming the e-commerce giant secretly made advertising more expensive on its website for more than a million companies. In a lawsuit filed in a federal court in Seattle, Amazon’s hometown, the F.T.C. and the states said Amazon inflated the costs that brands and marketplace sellers had to pay to promote their products to consumers, including the prominent “Sponsored Product” ads that appear in search results on Amazon’s widely used website. “Amazon has millions of advertising customers who were misled into paying significantly higher prices,” Andrew N. Ferguson, the chairman of the F.T.C., said in a statement. “These higher costs were largely passed on to American consumers.” Amazon disputed the