Rumors about Google releasing its own wireless service have been flying around for months. But now, after rumors and reports, the search giant announced Project Fi, its very own mobile virtual network operator (MVNO). 

Project Fi is an invite-only wireless service that is currently available for Nexus 6 users. The service is built upon Sprint and T-Mobile's wireless networks and won't require users to sign a contract. Subscribers pay $20 for access to unlimited talk/text, then they'll have to pay $10 per gigabite of data. So, users will pay $50 for a 3GB data plan, $70 for 5GB, etc.

What makes this service particularly interesting is that it refunds users their money if they don't use it. For example, if a user only users 2GB of a 5GB package, they'll get $30 back at the end of the month.

The service is powered through Google's Hangouts service, "which will allow you to place calls from your number on any Hangouts-enabled tablet or laptop in addition to your phone," TechCrunch reported. While the network is based on Sprint and T-Mobile networks, it seems to have rather spotty coverage. 

Project Fi's pricing scheme and data streaming is rather unique. "What makes Project Fi special and potentially more reliable than anything out there is that it dynamically switches between networks depending which of those is offering the best service in your area," Gizmodo reported. "Additionally, if there's pre-vetted public Wi-Fi available, it'll jump on board that network as well. The 'network of networks' has a lot of potential to be more reliable. If one network has an outage, the others can serve as support." 

Nexus 6 users can request an invite to Project Fi. It's unclear when Google will open the service to non-Nexus 6 users, or when it will not require an invite.