Project Fi, Google launched own Mobile Network

Say hi to Fi: A new way to say hello, Google Just Became a Mobile Carrier with Project Fi, Google Launches Its Own Wireless Service, Google's Project Fi service turns multiple phone networks, Google's Wireless service, “Project Fi,” is official, Google launched Project Fi, Is Google unveiling their wireless service
Last month we had reported that search giant Google is going to launch its own mobile network service on U.S, which was announced by Google on World Mobile congress. And here now company have debuted its new project called Project Fi.

The company has launched its Project Fi service in the United States exclusively for Nexus 6 owners. On the blog post, Google wrote that under Project Fi, $20 will the cost of basic plan which includes voice calling, text, Wi-Fi tethering and coverage in 120+ countries,with an additional $10 monthly fee for each 1GB of data you desire.

With this Google have made a pretty cool option under data plan. If a users didn't complete the allotted data in a month then he/she will receive a pro-rated amount refunded back to the account.
Its Simple - Never Pay For Unused Data.

Currently Google is working with T-Mobile and Sprint to expand its network coverage, with the 4G connectivity in most of the major metropolitan areas. Rest of other parts of America will be served with the 3G connectivity. 
At the mean time Project Fi is not available publicly and hence you have get the invite to use the service.  Users can request for the invitation from the Google Fi Page