Now that I've paid for the 4-night cruise, how much total cash can I really expect to go through during the trip? We're a family of four (kids are 8 and 3). We will not be buying alcoholic beverages on board and will probably sign up for at least one but no more than two family-friendly excursions, one spa treatment, a few diet cokes and tips are the expenses I expect to see. How much will that add up to? And what am I forgetting?

