The Federal Trade Commission has already gotten Apple to pony up. Now it’s going after Amazon over in-app purchases made by children. The FTC says it will sue Amazon over charges that the online retailer hasn’t done enough to keep kids from running up millions of dollars in unauthorized in-app purchases. Amazon had said it wouldn’t settle the case – because it had already refunded money to parents who complained about the in-app charges. The FTC settled with Apple over a similar matter for $32.5 million in January.