If you don’t have a credit card with lounge access, you may still be able to gain entry. Many airlines allow you to buy memberships or one-time passes for a fee. United Airlines, for example, sells one-time passes for its United Clubs for $59. American Airlines Admirals Club offers several annual membership options with fees of up to $1,650 for a household membership.
Other lounge networks don’t allow walk-ins to buy guest passes. For example, American Express Centurion lounge access is limited to certain cardholders and their guests.