Actually, Costco does NOT take credit cards, with the only exception being Amex.
They will takea Visa/Mastercard Debit card, but you have to enter the PIN. Debit charges are processed at a lower rate, since they're essentially an interface for ACH, and having a valid 4-digit PIN entered (plus buying stuff on a membership card) supposedly eliminates fraud.
(I was there this past weekend to capitalize on their great deals on flat screens.)
They will takea Visa/Mastercard Debit card, but you have to enter the PIN. Debit charges are processed at a lower rate, since they're essentially an interface for ACH, and having a valid 4-digit PIN entered (plus buying stuff on a membership card) supposedly eliminates fraud.
(I was there this past weekend to capitalize on their great deals on flat screens.)