The deals are for people in specific states of America, or it can be Senior Specials, specific dates, destination specials, and so on.
If you live in one of the states in America, you will have a good chance finding a deal there. Maybe also cheap flights.
I guess you will have to use a TA or a Cruise Consultant of RCL to book the cruise, as you will need to choose specific options in Agent to get the fares.
You can check out the Promowave website for more info: