Hi Stephanie,
I booked my cruise in September for July 2010. I paid my deposit by check over the phone. Then this month, I put more money down on it also by phone. There is no fee for this and my bank routing number and checking account number were kept on file, making it so easy. I just call the guy I booked the cruise with and tell him how much I want to pay.
This is the best way I can think of to pay for the cruise. Just paying some every month until it's paid. No finance charges and big credit card bill to worry about! You can, however, pay by credit card each month if you want to. Also, it has to be paid in full 2 months prior to your sailing date. 