what cards can be used to purchase groceries and gas at costco

Specifically VISA debit or credit... No longer using AmEx

Costco Citi credit card, Costco gift card and visa debt card.

They do not accept MasterCard. I believe that's the only one not allowed.

Costco Citi bank card, Costco gift card, visa,

U can also use a Costco gift card at the pumps..

Any Visa or debit card. Also have a ATM.

Any Visa card can be used

Atm

any visa cards