Google Fi is a cell phone service that only charges you for the data you use. It cost $20 a month for unlimited talk and text. WOW! Data is only $10 per gigabyte and you get a refund for the data that you don’t use. Say your plan is for 1 GB per month and you only use 500MB you will be refunded $5. Google Fi uses to carriers for its network T-Mobile and Sprint but also uses Wi-Fi and switches between them automatically. This requires a phone with special circuitry that does this action. The only phones doing this now are the Google’s Nexus 6, Nexus 5x and the Nexus 6p. More phones coming soon.