If you go carnival (and probably most other lines) you can get all your friends back home to go online and prepay for your drinks for you. Whenever somebody says to have a drink on them, tell them to go here

http://www.carnival.com/BonVoyage/Ad...t.aspx?pid=BAR

and for $19.50 buy you guys four drinks. I do it for lots of friends when they go, it's nice to have a few drinks waiting for them.