At least while at sea, you have to use the ship's internet access. Wi-fi is available on most ships these days - some have hot spots and others have shipwide wi-fi. The Freedom class has it everywhere on the ship. Of course, to use it you have to have set up a shipboard internet account and the meter is ticking.
The current pricing for RCI is 55 cents per minute unless you buy a block of minutes. Packages cost $28 for 60 minutes, $38 for 90 minutes, and $55 for 150 minutes. The minutes can be used either on your laptop or on the desktops in the internet cafe. It is the same account.
It isn't exactly speedy service and it can go offline periodically. If I were to judge it, the speed is generally in the 128 kbps range. Sometimes a little quicker, sometimes slower. The minutes fly by.