Vacations To Go offers a Carnival Cruise 7-Night Southern Caribbean Cruise for two with prices starting at $1,458. (If prompted, sign up for the free newsletter to see this deal.) That's $60 under yesterday's mention and the lowest price we could find for this cruise by $440. This roundtrip cruise aboard the Carnival Maguc departs from San Juan, Puerto Rico, on July 5 with stops in Cozumel, Mexico; Grand Cayman, Cayman Islands; and Montego Bay, Jamaica.