The number comes with the service. However, you can get free phone numbers without engagement and monthly bills. Free phone numbers are available if you know where to look, often in a package with other interesting features. This means that when you sign up for a free number from Google , and people call that number, you can have your computer, phone, and tablet all ring at the same time to ensure that you won't miss the call. One interesting feature you get with Google Voice is transcribed calls, meaning that you can read your voicemail instead of listen to it.