After hinting about it for months, Google on Wednesday finally unveiled its Project Fi low-price wireless service. The service debuted two months after an announcement from Google saying that it would begin providing wireless connections to smartphones. The cost of the service is $20 per month, which covers talk, text, Wi-Fi tethering, and international coverage in more than 120 countries.

Project Fi will also only charge users for the actual data  they use instead rather than a flat rate. The rate for that data will be $10 per gigabyte. If a customer signs up for a 3-gigabyte plan but uses only 1 gigabyte during a month, the user will get a refund of $20 at the end of the month. That contrasts with the policies of most wireless phone service providers that allow users to carry forward their unused data but don't offer refunds.

Nexus Only

At first, Project Fi will be available only to owners of the Nexus 6 device that Google developed in partnership with Motorola Mobility. Users can buy Nexus 6 smartphones to use with Project Fi directly from Google when they sign up for the service. The midnight blue Nexus 6 is available in two storage  sizes: 32 GB for $649 and 64 GB for $699.

The Nexus 6 purchase comes with a payment plan for those who would rather not pay the full cost up front. Users can pay over 24 months at $27.04 per month for the 32 GB option or $29.12 per month for the 64 GB option, with no interest or fees. However, a credit check is required to be eligible for this pricing.

"Similar to our Nexus hardware program, Project Fi enables us to work in close partnership with leading carriers, hardware makers, and all of you to push the boundaries of what's possible," said Nick Fox, Google VP of communications products, on the company’s blog. "By designing across hardware, software  and connectivity, we can more fully explore new ways for people to connect and communicate."

Besides lowering prices for data, Google also said its Nexus devices will connect to the fastest network  available. Rather than building its own network, Google is leasing out tower space from companies like Sprint and T-Mobile, and it says Project Fi will automatically switch over to a Wi-Fi network if it is running at a higher speed than what’s available on cellular networks.

Early Access

Google said that with Project Fi, users’ phone numbers live in thecloud , so they can talk and text with those numbers on virtually any phone, tablet or laptop -- meaning that if a user’s phone gets misplaced, the connection can be maintained via another screen.

Google has initiated a Project Fi Early Access Program to invite people to sign up for the service. Customers who live where the program has coverage in the United States can request an invite at fi.google.com.