Google Fi is an MVNO (mobile virtual network operator) telecommunications service by Google that provides telephone calls, SMS, and mobile broadband using cellular networks and Wi-Fi. Google Fi uses networks operated by Sprint, T-Mobile, U.S. Cellular, and Three. It has fair and flexible billing that starts at $20 / month for unlimited talk and text, and $10 / per 1GB until you hit 6GB. After 6GB, your bill is capped and data is free for the rest of the month. It's definitely one of the better options for when you're traveling abroad.