Google is launching its own mobile phone network in the US called Project Fi.
Subscribers will pay a base fee of $20 (£13.30) a month which will cover unlimited domestic voice calling and texting.
Data will cost $10 (£6.60) per gigabyte per month, and users will be charged only for what they use. Refunds will be issued for any unused data, the firm says.
At first, only owners of the Nexus 6 smartphone will be able to sign up to the network.
Google is renting the voice and data capacity from Sprint and T-Mobile, and will use existing Wi-Fi hotspots to provide the data service.
Users will be switched between the networks depending on signal strength.
The idea of a Google-created phone network was first publicly mentioned in February by Android executive Sundar Pichai, but little detail was provided.
Google wrote on its blog this week: “As you go about your day, Project Fi automatically connects you to more than a million free, open wi-fi hotspots we’ve verified as fast and reliable.
“Once you’re connected, we help secure your data through encryption. When you’re not on wi-fi, we move you between whichever of our partner networks is delivering the fastest speed, so you get 4G LTE in more places.”
Sprint reportedly has the right to renegotiate the deal if the popularity of the service grows above a certain size.