Cruise.com via ShermansCruise offers a Carnival Cruises 5-Night Caribbean Cruise for Two with prices from $748. (On the landing page, scroll down and click "Book Now" next to the December 2 sailing date.) That's the lowest price we could find for such a cruise in December by $180. This roundtrip cruise aboard the Carnival Conquest departs from Ft. Lauderdale, FL, on December 2. Additional fees may apply. Book this travel deal by August 31.