I have used RCL gift certificates in the past to apply against the cruise cost if that helps.
Edited to add: I found this on Raise's website:
"There are no limitations to the number or dollar amount of cards that can be used, but reservations MUST be made over the phone through
Royal Caribbean directly. To reserve your Royal Caribbean cruise vacation, call Royal Caribbean at 866-504-3941 and reference this Voucher as well as Agency ID 312236*. VOUCHER MAY NOT BE APPLIED TO A RESERVATION MADE THROUGH A
TRAVEL AGENCY. Please allow for 5 business days for Voucher Activation. Deposit is required at the time of reservation. After making your cruise reservation, email a copy of the Voucher along with your cruise reservation booking number to
SharedServicesGiftCertificateRedemption@rccl.com. The value of the Voucher will then be applied to your cruise reservation. Cannot be redeemed on discounted trips. Vouchers can only be used to book a new reservation. Cannot be redeemed through any third party booking site. Card may not be applied towards on-board credit. Vouchers cannot be redeemed at
http://royalcaribbeancertificates.com/redeem.aspx."
I believe there have been some threads over on cruise critic about these cards, and if I remember correctly, you have to redeem the vouchers when you make the booking. I'd call RCL directly and talk to them about what you want to do before you buy some and find out you can't use them.
