I have always used Google voice to call home from here in Italy. It only charged me 1 cent a minute to call the states. I even use it to call landlines here in Italy because it's only 2 cents a minute as compared to the 12 cents a minute they charge me to call a land line from my cell phone. But it just got even better!
If you have a .mil email address you can add it to your google voice account info (if you have a gmail account log in with that info, if not, create a google account) and it emails you at the address to confirm and then you are signed up for FREE calling to the states from anywhere overseas! Thank you google voice! This would have been nice to have when my husband was deployed!