IF you read the details for the cruise cash, any amount not used with be forfeited! So if you choose to buy some, don't by too much. You can always add cash on your S&S account once you run low!
2011 - Elation from Mobille
2012 - Triumph from Galveston
2013 - Conquest from New Orleans to MoBay, Jamaica, Grand Cayman, and Cozumel