How to contact someone from a cruise ship?

I'm going on a cruise in the morning so this is kind of last minute (sorry!). I'm going with my dad and was wondering how I can contact my mom back home.
I have an iPhone so I can download any apps tonight to use. I was looking for relatively cheap ways of calling/texting back home. I've got the Wi-Fi figured out, but not calling and texting. Any help is greatly appreciated!

Use your I phone while in port. You can ask any crew member where the free Wi-Fi is in any of the ports you are going to. They all know the free places. Often it is right at the port.

You can text with imessage free even internationally. You will have to pay for Wi-Fi on the ship though.

There's a phone in your room on the ship, only problem is; they charge RIDICULOUSLY. Never seen a charge for a phone call that much! It was crazy