FILE - In this May 4, 2010 file photo, a customer looks at wide screen sets advertising American Express cards at a Costco store in Mountain View, Calif. Costco shoppers who have been limited for years to American Express credit cards may be able to pluck a new option from their wallets or purses next year when an exclusivity deal between the two companies expires on March 31, 2016. (AP Photo/Paul Sakuma, File)