The cost of the soda card on Royal Caribbean is $6.50 per day. A seven day cruise would be around $45.50.
If you drink more than three sodas a day it will be worth buying the package. I think Paul confused the total cost of the package and not the cost per day.
The included beverages are water, coffee, tea, lemonade, iced tea and juices and milk at the buffet or restaurants during meal hours.
There is plenty to drink but if you want a soda, beer, mixed drink, fresh squeezed juice, or specialty coffee you will pay extra for them.