The new Vonage Mobile app for Android and iPhone is a free app that allows you to make VoIP (Voice over Internet Protocol) phone calls and text messaging. Vonage has offered home VoIP service for some time. The mobile app does not require you to have a current Vonage account to use.
The Vonage Mobile app is free, and is available for Android 2.1 and Apple iPhone and iPad. As of right now, you can place free VoIP phone calls to any phone in the US, Canada, and Puerto Rico, but this is a limited time offer. You can make free phone calls and texts to other Vonage Mobile users. If you are using your 3G/4G connection, calls will count against your data usage, but not your minutes.
Here is a chart with calling rates for Vonage Mobile
Disclosure: I was paid to write this article, as well as for the ad on the top of this site