The following was originally posted on my Jessica in Ukraine blog 3 years ago. I have included it here, with some editing, for those who might be interested.
A few years ago, I discovered Google Voice, which is turning out to be more beneficial than I'd first thought. Now, I have figured out how to use Google Voice (sometimes in combination with my Skype account).
Originally, I used Google Voice in the US so that one of my friends could call a number (local for them) that would forward the calls to my cell phone. I had set up two different numbers (with two different email accounts), and one of them was with a Maryland area code for my "experiment."
In the States, this is how Google Voice works, with a centralized voicemail for all your phones.
Friend --> GV number as intermediate number --> Your phone (cell, home, work, or all of them) rings
While in the US, I have a Verizon phone with a monthly contract. This contract is put on hold while I am overseas, so I don't pay for a phone I'm not using (so a two-year contract turns into three years).
Before I discovered Google Voice, I used Skype if they are a Skype user or if I am calling a 1-800 number because these are free (or I could use an old phone card that still had credit). Sometimes I used Skype to call phones (for the whole conversation or to have them call me on Skype), but this costs about 2 cents a minute, so I usually use it for calling internationally (as in, back to my Ukrainian friends) during the summer.
Here is where Google Voice comes into play! If there is no answer on any of the phones, Google Voice records and transcribes your voice messages and notifies you by email (which can be VERY entertaining sometimes). My family (or others I am trying to contact) can leave me voicemails, which worked out VERY well in the spring of 2011 while I scheduled services at churches. You can also send a free SMS to any US phone. Now, I can use my Google Voice number as my "home" number so that those in America can contact me! It's long-distance for my family, but at least it's not an international phone call.
I also switch between using Google Voice and Skype for making other international calls, depending on where I have credit. Calls to the US (and maybe Canada) are free, but calls to other countries cost a few cents per minute. You can view the rates on their page. For some countries, the rates are lower than Skype's!
The only caveat that I can think of at this time is that the number probably needs to be set up while you are stateside. They will send a verification code via text or audio to your phone number, and you must be able to get that code. Perhaps an option is to use a family member's or friend's phone number, and change it to your own number once you are stateside again.
This does get confusing for some people, particularly my grandparents, who still remember both phone numbers. Also, if I send an SMS directly from my phone, it will show my Verizon number and not my Google number.
Unfortunately, Google Voice may not have local numbers for all areas, nor can it forward calls to international phones (that would be AMAZING, though). For now, Google Voice is still rather practical.
When you're a missionary or expat, you've got to be thrifty and inventive with what you have.