Best Plan for International Calls? (Skype vs. MagicJack vs. Google Voice)

First off, I’ll just admit that I’m an idiot when it comes to VoIP stuff. I have used Skype for video calls (never to land lines), and that’s about it. I have never used MagicJack or Google Voice, although I am somewhat familiar with the basic concept of using the Internet to make/receive calls.

I’m about to move to Costa Rica for two years. I’m taking an unlocked smartphone but I have no idea yet exactly what sort of plan I’ll end up with. So in addition to mobile calling, I want to have a backup plan using MagicJack, Skype, or Google Voice. But…I don’t understand exactly how it all works! I’ve been reading up on them but it’s all blurring together.

All I want is to be able to make and receive calls back to the U.S., using a computer OR a handset, for free or cheap. I also want to make sure that people calling me from the U.S. don’t get charged for the call. I assume I need to get a local (U.S.) number before I leave.

Bonus points for the plan that would somehow allow me to integrate my (as yet unknown) international cell phone into it all (maybe using an app?).

Is one of the 3 (Skype, MJ, GV) easier/better, or are they all pretty much the same?

Advice? Opinions? Please?

I can only tell you what it’s like here in the UK.

I use my computer (with microphone, speakers + webcam) to call the US using Skype on both phone + video calls to both landlines + cellphones.

It’s free (including the download of Skype software) and satisfactory.