Google's 'Project Fi' wireless service is officially here

As rumored, Google on Wednesday took the wraps off its new wireless service, called Project Fi, and it offers a new take on how users pay for data.

Project Fi is invite-only for now, and it offers just one type of plan that costs a $20 a month, plus $10 for every gigabyte (GB) of data, Google revealed in a blog post. The big innovation: Google will refund, in the form of a credit, any money spent on data you didn't use. That's a significant change from the major carriers, whose revenues depend on charging a flat monthly fee for big buckets of data.