I would definitely recommend you find the biggest and newest ship possible to avoid the sea sickness. I was on a tiny ship and it was awful but my FI went on a trip on a large boat and said you could barley feel it. The last day sticker shock of the drinks does suck. On the cruise lines I have experience with (Carnival and Royal Caribbean) the pop is included but the alcohol is not and no pre-pay options. Some people smuggled hard liquor on and then used the free pop to make their own mix drinks.