Placing calls with Google Voice is almost the same as placing calls via your mobile carrier, depending on whether you have a Google number and how you have configured Google Voice on the phone.
1. Call a contact just as you would without Google Voice.
2. If you’ve configured Google Voice to ask whether you want to use it each time you place a call, touch Call with Google Voice in the dialog. If you’ve configured Google Voice to use it for all calls, this dialog doesn’t appear.
3. Google Voice displays a message, reminding you that you are placing the call via Google Voice.
If the call is a toll call, Google Voice plays a message with the per-minute charge and the number of minutes at this rate you have remaining in your Google Voice account.
Note: Using Google Voice for Android app to place your domestic and/or international calls will still use normal minutes from your cell phone plan.
If you don’t want to use your normal minutes, use GrooveIP to make Google Voice calls.