We just got back from Carnival Glory on a 7 day cruise. I bought 3 soda cards and it cost us $101.00. The cards are $4.00 per day for children and $5.00 per day for adults, you purchase them onboard at any bar and the one card is good for the entire cruise. There is also a 15% gratuity added to the cost. It is well worth it because it covers not only sodas but any smoothies or non-alcoholic versions of drinks they want. My daughter only drinks clear sodas for example so she got mostly shirley temples which are like 2.50 each normally, so if she bought two a day we would have more than paid for the card...it's a good deal.