Ahoy there Julie -
It is wonderful that you are planning and budgeting for a Disney Cruise, and you can bet your pirate crew will have a great time on Disney Cruise Line. Absolutely yes, Disney Gift Cards are acceptable payment on all Disney ships. Sailors can pay for all or part of their trip using a Disney Gift Card. Using gift cards is a great way to plan your budget and save along the way. Although Disney does not offer a direct discount, Disney Visa cardholders earn reward dollars that can be converted to Disney Gift Cards.
Another way to save is to look for discounts at grocery stores and major retailers. If you keep watch for sales, you can find instant rebates on your card for cash, and some stores offer gas credits too. If you plan to pay for your trip with the Disney Gift Card, then you will need to call Disney Cruise Line directly to make a payment at (800) 951-3532. You can schedule these payments according to your budget.
In our family, we also bring Disney Gift Cards on the ship to help us pay for onboard spending. At the start of the cruise, we drop off gift cards at Guest Services and they provide a credit for all of our onboard spending, tips and even excursions. The cards can be used in the gift stores onboard but for everything else we use our Key to the World card for payment. You can get a credit back for unused money that will be put back on your gift card. Julie, I hope that you have fun planning and budgeting for your trip and let us know if you have any other questions.