what can onboard credit be used for on celebrity?
['Spa services, such as massages or haircuts.', 'Alcoholic drinks (including beverage packages)', 'Specialty (up-charge) dining.', 'Shore excursions.', 'Gratuities (aka service charges)', 'Onboard retail purchases (gift shop merch)', 'Gambling and other onboard games.', 'Internet access.']