Vacations to Go offers a Carnival Cruise 4-Night Western Caribbean Cruise for Two bundled with a $50 onboard credit with prices starting at $558, as provided by Dunhill Travel. (If prompted, sign up for the free newsletter to see this deal.) Assuming you use the credit, it's the lowest price we could find for this cruise by $30. This roundtrip cruise departs from Miami, FL, on May 12 with stops in Key West, FL, and Cozumel, Mexico. Some restrictions may apply; fees, government taxes, and fuel supplements are additional. This travel deal ends April 8.