Use Sim Cards Smartly To Save Money While You Are On The Move
You can make free international calls using VOIP services, but when you don't have internet you are forced to use costly sim cards. While it is not possible to make free international calls using your sim cards, you can reduce the costs of your calls by using a number of tricks: you can buy local sim cards to receive calls for free and beat roaming charge, or you can communication simply through free messages.
Alternately, you can order sim cards from specialist international call operators, and get really cheap rates for international calls to particular countries (as low as a couple of cents per minute). You can also upgrade your sim card by buying international add-ons and make cheap international calls after paying a lump sum to the phone company.