Google Fi SIM cards are now available on Amazon

The card costs $10, but you get $10 back on your first bill.

Google has begun selling Fi SIM cards on Amazon. The cards will set you back $10 (with free Prime shipping), but they’re really free because Google will give you a $10 statement credit on your first Fi bill. Of course, in exchange, you're agreeing to let Google peek into yet another part of your digital life.

Google Fi is flexible — Fi is a mobile network from Google, and it competes with the big players like Verizon and AT&T by offering flexibility. For instance, as a single user, you can choose an unlimited data plan for $70 a month, or Google will let you pay $20 a month for unlimited calls and texts and $10 per gigabyte of data until you hit 6GB, after which any additional data you use is free (but you will get throttled at 15GB, or 22GB on the unlimited plan).

Plans for groups are cheaper with the base price of service falling to $45 per user for unlimited plans with six or more users and $16 each for the pay-what-you-use option. All packages are billed month-to-month so you can add or remove users with ease, and you can keep your existing number if you're coming from another network.

Google Fi operates as an MVNO — Meaning Google doesn’t actually have radio towers of its own but instead piggybacks off the networks operated by Sprint, T-Mobile, and U.S. Cellular. It also works abroad — and you won’t pay any additional roaming fees for texts or data service, while call charges will vary per county, with many billed at $0.10 per minute. This is definitely nice because I’m in Canada right now and T-Mobile has been charging me liberally for international data.

You can only finance Pixels or a Moto G7 — The only noteworthy downside is that Google Fi doesn’t offer many phones directly (it's pretty much Pixels and one Motorola). If you want to use an iPhone or another device Google Fi doesn’t offer you’ll either need to have it already, or you'll have to buy it without carrier financing. Similarly, Apple's annual upgrade program doesn't accept Fi users.

But if you've got a working, supported phone, you're keen to escape your current operator and potentially save some money, or you're looking to get a Pixel, Fi might be worth a look. Especially if you can rope some friends or family members into switching with you.