Not Free – Callbacker: Calling App & SMS Review

The interface is very simple and easy to use. However, whenever I try to make a call it tells me that I don't have enough credit. Also whenever I finish typing a number it shows a certain amount of money to the side. If this app is free why does it keep telling me all this? Why is there a "Balance" page??
Review by Zuxo Powell on Callbacker: Calling App & SMS.