Technically, that's not possible. But as the others said, there are apps you can download to be able to text for free. The one I like using is called TextNow. When you sign up, it asks you for your local area code as it will assign you a phone number. When you text, it comes to the other person as a true SMS message (they don't need to have TextNow installed) and they can reply like they reply to any other mobile number. TextNow also offers calling and I just haven't used it but I don't believe it costs a lot.