You can buy fun ship dollars to use as credit on your sign and sail card
so you dont have a bill or much of one when you cruise.
You can order them on carnivals web site on the right side of the site
it will say gifts click there and you will find them, or call the number on the site
and order them. You can also order bar credits for drinking if you wish.
Both are nice to have. You have to have a cruise booked I think to buy
I always have atleast one cruise a year booked a year ahead so I have lots of time to buy them.
you can get them in different amounts.
Then I turn them in at the pursers office the first day of the cruise.