Cruise.com via ShermansCruise offers a Carnival Cruise 4-Night Mexico Cruise for Two, with prices starting from $378. (On the ShermansCruise landing page, scroll down and click "Book Now" next to the September 10 sailing date.) That's $50 under our mention from two weeks ago and the lowest price we could find for such a cruise now by $40. This roundtrip cruise aboard the Carnival Victory departs from Miami, FL, on September 10. Book this travel deal by August 31.