There is no additional charge to make a Face Time call on any phone. Face time however does require Data, weather it be WIFI data or Cellular data. If you dont have cellular data on your line you will need a wifi data so it will come out of your wifi data. if you dont have wifi, it will try to use the data from your data plan ,if you do not have a data plan you might get charged for it, check how much your data rates are, by calling rogers. This will be the same for both sender or receiver.
The reason why most of us do not worry about this is majority of people have data plans included with their phone package for this very reason so they do not have to think about this.