Google Fi is a MVNO 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, and U.S. Cellular.

Google Fi has an unlimited plan and a flexible plan. With the Flexible plan, you start with unlimited talk and text for $20 per month for one line. You only get charged for the data you use at a rate of $10 per 1GB. Once you’ve used 6GB of data in a month, your data charge is capped at $60 for the rest of the month, but you continue to get data service. You can use as much data as you want for the month without paying over $80 total ($20 base + $60 data). The only caveat here is that once you hit 15GB of total data usage, your speeds are slowed to 256kbps — alternatively, at the 15GB point you can choose to start paying $10 per GB again for full-speed data if needed.

If you know you are going to be using more than 15GB regularly, you can go with the unlimited plan starting at $70 per month with one line. You don’t pay per gig on this plan but your speeds will be slowed at 22GB of usage. You get all of the benefits of the flexible plan plus free calls to more than 50 countries and 100GB of cloud storage with Google One.

You can save some money on your plan if you have multiple lines with the cost per line on the unlimited plan coming down with each additional line up to four, up to five on the flexible plan. You can have six lines total but your cost per line will be the same as four. Additionally, you can add a data-only SIM for free so you can share your data with another device without needing to create a hotspot.