Talkatone is a free unlimited Internet calling service that allows you to have a number in the United States. The app automatically generates one that you can use to send messages and make calls to other numbers in this country without long distance charges or international rates.
Your U.S. phone number
With this app you can call people who have a number in this country but also send messages that include text, photos and animations in GIF format. You can also call people who have a number in other countries. You won't need to hire any company as it works through VoIP protocol (you just need an Internet connection).
All you have to do is allow the app to access your address book and you can call any number in it. However, please note that the app has restricted calls to emergency services. Charges also apply to users who call and message non-Talkatone users. In other words, to call for free you must both be registered with the service with a number granted by the service.