Costco accepts a variety of payment methods, including Visa cards, the Costco Anywhere Visa Card by Citi, most PIN-based debit/ATM cards, Costco Shop Cards, cash, personal checks from current Costco Members, business checks from current Costco Business Members, traveler’s checks, EBT cards, and mobile payment options such as Apple Pay, Google Pay, and Samsung Pay. However, Costco does not accept American Express, Discover, or Mastercard credit cards in its warehouses, although you can use Discover or Mastercard credit cards online (but not American Express) at Costco.com or in the Costco app. Costco members are allowed to purchase Costco Shop cards online with a Mastercard, Discover, or Diners Club card, which can then be used at the warehouses. Its important to note that Costco Warehouses and gas stations do not currently accept cards from any network other than Visa, so American Express, Mastercard, and Discover credit cards cannot be used for in-warehouse Costco purchases.