http://www.parkrideflyusa.com/mia-miami-airport-parking/cbm/parking_rates.php
That place is a park/sail facility that charges $10.50 a day, so for 5 day it would be $52.50 and a 7 day for $73.50
2009, Sept 7: Carnival Destiny : Cabin 6344 Grand Turk, Half Moon Cay, Nassau
2007, June 23: Carnival Liberty Cabin 6456: San Juan, Antigua, St. Thomas, Tortola, Nassau
2006, May 14: Carnival Miracle Cabin 8232: Cayman Islands, Cozumel, Belize, Costa Maya

