Royal Caribbean Cruise Line is offering a 100 dollar on-board credit that can be used and received by any traveler who purchases a Stateroom. If you book two Staterooms you will receive two 100 dollar Caribbean Cruise credits. I read the terms and conditions of this limited time deal and Caribbean Cruise states that they reserve the right to deny this offer based on availability which can occur without notice.
They then go on to state that the best way to cash in on this 100 dollar credit is to book early (30+ days ahead), a deposit is also needed ahead of time, book online and make sure that the Caribbean Cruise you choose has a yellow dollar icon next to it. There are many more conditions but I think the safest way to receive this deal is to find an appropriate Royal Caribbean Cruise early and then call a booking agent to confirm the credit.

The onboard credit can be used for activities like spa treatments, shopping, shore excursions, food and more.

Here is the Royal Caribbean Cruise link: http://leisure.travelocity.com/Promotions/0,,TRAVELOCITY|4652|cruises_main,00.html?WA1=03010&WA2=169543496&WA3=23395343&WA4=0&WA6=536661;