Vacations to Go offers a Carnival Cruise 4-Night Mexico Cruise for two, bundled with $50 Onboard Credit with prices starting at $536. Assuming you'll use the credit, that's the lowest price we could find by $50. This roundtrip cruise aboard the Carnival Fantasy departs from Mobile, AL, on January 4, 2018, with one stop in Cozumel, Mexico. Book this travel deal by November 30.