Only "charges" are that you use use minutes like you would with any call...my cell plan is unlimited calls and texts so not an issue. Data is not an issue 'cuz it's off. We have never seen any additional costs added other than when we used the one day $10 TravelPass for calls from the car. During our last trip in July to Brittany, FR my better half talked to her sister in FL for over an hour....that was the big test.....no charges