Well part of that is determined as to which cruise you are on. Is it the 3, 4 or 7 night?
Once you figure this out, you can look up the excursions and how much they are. Generally, you can find them for $30-55 per person. There are definitely more expensive ones.
Drinks: There is now a soda drink station for free pop, but it is only in the one area. If you get a soda from a bar, you will be charged.
The kids may like the smoothies that are offered at dinner, at the shows. They are around $3.
The alcholic drinks are not that bad, around $5.
The spa runs anywhere from $45-way up there. There is a list of spa services with prices.
If you can find the spa and excursion price lists that will really help you out.
As for drinks, we only spent around $50. I had a few drinks here and there as did hubby. Usually 1 or 2 at dinner.