As bOB said, the average price per minute is around $0.75. And, be advised, the connection time is slow. If at all possible, cut yourself off from the Internet for the week. I think you'll find your vacation will be much more enjoyable (and you'll save a lot of money). Of course, if you're so vital to wurk that they absolutely have to be in touch with you then, I'm sure, your company will pick up the tab for the Internet connection.
And, the next question .... Cell Phones. Yes, you can use them on the ship. But, be prepared for an additional $9.75 per minute to be added to your monthly cell phone bill. You see, when you call, the ship's antenna takes the call. They shoot it up to a satellite and then it's relayed back to "the world". That make it a Satellite Call, not a cell call. Oh, and don't forget to add the international roaming to your long distance/out of area roaming charges.
Bottom Line? You're on vacation. Turn off and lock up the electronics. You'll enjoy your cruise a lot more!