Cruise.com via ShermansCruise offers a Carnival Cruise 7-Night Eastern Caribbean Cruise for Two with prices starting at $798. (On the ShermansCruise landing page, scroll to the bottom and click "Book Now" next to the April 15 sailing date.) That's the lowest price we could find for such a cruise this April by $40. This roundtrip cruise aboard the Carnival Fascination departs from San Juan, Puerto Rico, on April 15 with stops in St. Thomas, USVI; Barbados; St. Lucia; St. Kitts; and St. Maarten. Book this deal by February 28.