Hi jaw99, welcome to Cruise-Chat. Here is a link to HAL's web page, they don't state the rates, but they do state there is a charge. With Princess, you can purchase packages and the rates vary from $.50/minute-$.75/minute, depending on the package. This should give you a ball park idea. Best wishes for a fantastic cruise and once again, welcome aboard!
Just be aware that even at 50 cents per minute the service is slow & charges can add up quickly.
It does take some planning to keep from racking up a hefty wi-fi bill. When on a cruise, I type up notes for this forum in Word and then quickly copy and paste them into the message threads. Of course, you need to have your laptop in order to do the time management thing.
I was just reading that on the Caribbean Princess that they have free Wifi access for Platinum & Elite members. You're still limited by the total of free minutes but those with a laptop can at least connect without using Princess's computers. This is supposedly a test program that might spread to the other ships.