So you can’t actually make free calls with Google Voice alone. However, what you can do is send free text messages. These days, I text WAY more than I talk. It’s a vital communication channel and Google Voice let’s you do it for free.
Gauva is an app developed by the Gizmo5 team that let’s you make free calls. Better yet, since it’s now a Google acquisition, you can sync the app with Google Voice (and your Google contacts). Combine this with your Google Voice account and make free calls and texts!
Skype mobile™ on Verizon
Skype let’s you call any number for free, or call your friends right on their PC with your Skype contact list. Still no video calling, but it’s in the works.
Cheap international calls
Rebtel is likely the best calling app out. It integrates seamlessly with the Android contact manager and the built-in dial pad so you don’t have to explicitly fire up the app to get things done, just dial away like normal. Best of all is that the app makes absolutely free calls to anyone with the app installed and to over 50 countries. Unlike most of the included apps here, Rebtel doesn’t need a wifi connection to work. It’s compatible with a 3G or even basic CDMA connection.
fring Free Calls, Video & Text
This app is included because it’s the best free video chat client available for the Android. It will let you chat for free, over a wifi connection, using Skype, MSN or Yahoo! video chat contacts.