If you are looking for a Free Voice Changer, I think I can help you out. What is discord? For people that don't know, discord is a free software used for text and voice communication on Xbox Live. It's aimed mainly at Halo players. The application gives users a fair amount of freedom for those who want to communicate with others in a group.
With this program, you can basically record your own audio message onto any Xbox Live-related file. You can then send this recording to other players/audience via Xbox Live. To do this, all you need is a recorder/editing program and a quality microphone. A simple recording can be recorded into an audio file with Windows and then sent through whatever application you're using for the application.
This free voice changer uses the Windows Audio Interface (IA) to enable text/audio chatting. All you need to do is open up the Windows Live messenger and go to "chat" - on the bottom of the page you'll see a button for "chat options". Click on this button and a recording of your voice will be loaded into the application (you'll need a quality microphone for this).