Earlier this month, Facebook started testing a free VOIP calling service for all iPhone Facebook Messenger users in Canada. Facebook is now slowly rolling out this free service to its U.S. users.
In order to make a call to one of your friends who also uses Messenger on iPhone, all you need to do is start a new conversation with them. In the top-right hand corner you will see an "I" button and "free call" button. You will need to touch both buttons to make phone calls.
This feature will be extremely beneficial for those who have bad cell phone service while you're at home or at work, and if you want to save your minutes. This may be very bad news to phone carriers who rely heavily on their users’ monthly minutes.