I've just signed up for my first cruise to the Southern Carribean in April on Celebrity and I was hoping to get some clarification on a few cost questions. First, I don't need an alcohol package but it's likely I'll be getting a drink or 2 so I'm confused on how you pay for them. Is it billed to you at the end of the cruise or do we pay cash for those seperately? What about the tip? Second, on shore excursions, if I book them now when do I have to pay for them? Before I cruise or is that on the bill at the end too?