I have a small netbook (I think I paid like$159 for it) with a headset and microphone and I have made several free or extremely cheap phone calls to the U.S. From all over North and Central America, the Caribbean, England, Spain, Ireland, North Africa. If I can find a wifi signal then I can call someone using skype. We've also used a Sony PSP to make Skype calls as well and check email. It's a little more difficult to manipulate, but it is small and would fit in a large pocket.
One time we were anchored a little way off Grand Cayman and we were able to pick up a wifi signal from a nearby hotel that must have been amplified or bounced by the water and we were able to call home from the balcony of our room.
Unfortunately I have never been able to get it to work with the ship's wireless internet though.