On a 7 day cruise Carnival will put a $400 hold on the credit card account you provided to them. If after four days you have exceeded this $400 they will add another $400 hold.
If your S&S account is a cash one you will be required to put down this amount in advance (in cash of course).
You asked how does this S&S card work. It is every passangers ship ID card. Is is your onboard charge card for all your purchases. You can have as many people as you wish all charging to the same account if you wish, or seperately. On the last evening of the cruise you will receive a statemetn of account (you will also get one on the fourth day). Verify all your charges and proceed to the pursers desk to pay your bill. If you wish you can pay it completely in cash or as set up on your credit card. Or if you wish do nothing and your credit card will be charged.
We carry two credit cards when cruising. One strictly to take with us off the ship (with a spending limit of only $1.000). and the second for our S&S account (or as a back up to our other card). Last cruise I had $200 in travelers cheques left over and we put it towards our S&S account.
It works all to easily! If you are on a budget you might want to bring travelers checks and use them for gambling and off ship purchases. Use the S&S card for your tips and any excursions you want to go on as well as any drinks you purchase. oh and just a hint .. don't use the phone in your room! Bring a calling card to use in port! This way you don't have a heart attack when you see your S&S bill =)
Star Princes -- my honeymoon cruise =)
The card will be with your documents. Best to complete it prior to arriving at terminal. This will expedite your check-in process. I also think it helps to use the online "Funpass" registration prior to boarding.