I am pretty sure that the Carnival standard is a $3.95 set-up/activation fee and then either $.75 per minute or 100 minutes for $55 or 250 minutes for $100. We generally get the 250 minutes for a week since we (at least 2 of us) check our email twice a day.
I believe Barry is correct. Altho I never got the minutes package because I was not on long enough. Now it is true you will see many internet cafes in port and they are quite abit cheaper however, do you want to waste valuable precious time in port surfing on the net. I would check my emails once a day. All I would look for was anything from my kids, send them a response and I was off. I may have spent on the average $30.