That's a good question and one I'm interested to read the answer to as well. When we went last year, the only accepted form of payment was your 'key to the world', a.k.a. your room key. I'm not sure how they would provide change for your Disney Dollars, since all of the transactions are handled through the Key Card. I know that the DisneyCruise web site has a link to e-mail any questions, and two weeks ago when I e-mailed them a question, they replied within hours. You can always try that route. Good luck, and post whatever new info you find out for the rest of us, okay?