A good VoIP mobile app while travelling?
I have a CDMA variant of Samsung Galaxy S4 so country specific SIM card is out of question. I recently checked this relatively new but well reviewed app Global Call and also their contest on facebook through which I might win free credits so I am interested in using this one. However, some have suggested using Skype and Viber but they will not be as economical as Global Call. Can you guys suggest which one I should go for?