Google just announced Project Fi, its new MVNO wireless service for the Nexus 6. Google hopes to shake up the industry with its control of the hardware, software, and network. It's sort of the Google Fiber approach: move into a market with a new pricing scheme and new technology and hope the pressure of competition makes the internet better for everyone.

Project Fi (Wi-Fi + Sprint + T-Mobile )

Google Fi combines Sprint, T-Mobile, and Wi-Fi into a single network. This isn't Sprint or T-Mobile; it's Sprint and T-Mobile. Your phone is subscribed to both networks and jumps between them, which means the Nexus 6 will be hopping from Wi-Fi to CDMA to GSM to LTE as the situation dictates. Calls, texts, and data can seamlessly switch between T-Mo, Sprint, and Wi-Fi, and calls and texts can be routed to any secondary devices that have Hangouts installed. You're allowed to tether, and your data plans work in over 120 countries, but only at 3G speeds.

Google says they have "millions" of high-speed Wi-Fi hotspots across the country, and your connection to them is encrypted. The biggest downside is device selection: for now it only works on the Nexus 6.

Google Fi's pricing is a mandatory $20 unlimited talk/text plan plus $10 per GB of data—so 3GB of data and your total bill would be $50 a month. Tax is not included in the plan, so expect another 10%-20% increase on top of that. The main difference is that you don't pay for the cellular data you don't use. If you're paying $30 for 3GB of data and only use 2.4GB of data, you get $6 off your next bill. This has the potential to save a lot during light usage months.

Republic Wireless (Wi-Fi + Sprint)

Republic Wireless is probably the closest existing service to Project Fi. It also offers a "Hybrid Network" that primarily uses Wi-Fi and seamlessly switches to Sprint when Wi-Fi isn't available. Like Project Fi, calls and texts work over Wi-Fi, but this requires custom software built by Republic Wireless, which limits device compatibility (only the Moto X 2014, Moto X 2013, and first gen Moto G, and E work) and slows down device updates. While it doesn't offer Project Fi's cash-for-used-data deal, users can change their plan up to twice a month.

Republic Wireless offers a lot of "edge case" plans that might save you over Project Fi if they happen to fit your mobile lifestyle. You can get a phone number for dirt cheap—only $5 a month—but that's with no cellular access, it's unlimited talk and text over Wi-Fi only (and of course, data will work over Wi-Fi). There's also a $10 unlimited talk and text over Wi-Fi and cellular, still no cellular data though. There's a $25 3G-only plan with 5GB of data which then gets throttled unlimitedly. Things finally get comparable to Project Fi and other plans with a $40 per month plan for unlimited talk, text, and 5GB of data that then gets throttled.

This $40 for 5GB plan is the only 4G data plan on Republic Wireless, but if you use exactly 5GB per month, Project Fi would cost an extra $30.

Straight Talk (AT&T or T-Mobile)

Straight Talk doesn't have any kind of special Wi-Fi functions, but it makes up for that by using AT&T's network. Most people would agree that AT&T's network is superior to T-Mobile or Sprint. Coupled with low prepay pricing, it's a great combo of a good network at a low price.

For an outlier plan, we've got unlimited talk and text with 100MB of data for $30. Straight Talk has one and only one real data plan though, and that's a $45 plan for unlimited talk, text, and 3GB of high-speed data with unlimited throttling. If you use exactly 3GB of data, Project Fi would cost you $5 more. Straight Talk also has a $60 3GB plan with "Unlimited Mobile to Mobile to Mexico, China, India & Canada plus select international landline destinations."

T-Mobile Prepay (Wi-Fi + T-Mobile)

T-Mobile lets you do Wi-Fi calling, too, just like Fi and Republic.

T-Mobile prepay has a few outlier plans, but the most interesting one is $30 for 5GB of data with unlimited text and throttling, and 100 minutes of talk. If you never make phone calls, this plan is amazing! Oddly, it's only available online or at Walmart. T-Mobile wants to keep it a secret.

In terms of regular plans, things start at $40 a month for unlimited text, talk, and 1GB of data with unlimited throttling. Project Fi would save $10 over this. The 3GB plan ties Project Fi, and the 6GB plans beats Fi by $10.

Ting (Sprint or T-Mobile)

Ting is made up of entirely outlier plans and seems geared toward extremely light usage users. It's entirely à la carte with no unlimited options. You pick the number of devices, minutes, texts, and MBs that you want per month and the calculator spits out a price. The prices come out really cheap if you pick low items, or if you go data-only, but they quickly ballooned into contract-level rip-offs if you need a lot of data.

It's hard to compare Ting to anything, really, because it doesn't offer the unlimited text and talk that the others do. If you're a low-usage user though, check it out.

Project Fi pricing: Good for people with fluctuating data usage, bad if you can find the perfect plan elsewhere

This chart is our best attempt at a big wrap up of comparable (and only comparable) pricing plans. There are many, many caveats about this chart. We tried to be as fair as we could, but:

Not everyone offers pricing at different data levels, so we used the value for a higher level, the same way a customer would.

Sprint and T-Mobile prices are for prepay, Verizon is on contract as an example of what that's like.

We ignored false claims of "unlimited" data—this chart is only full-speed data. Straight Talk, T-Mobile, and Republic Wireless will let you keep using data at drastically reduced speeds. Straight Talk throttles at 3GB (and won't go higher) and Republic Wireless cuts out at 5GB.

Straight Talk's "Talk and Text only" plan actually comes with 100MB of data.

Ting's à la carte pricing makes it very hard to fit on this chart. We went with one device ($6), 500 minutes ($9), 100 texts ($3), and the stated amount of data. We had to pick something.

Verizon's and Sprint's plans don't have a 5GB tier; we listed the price for 6GB.

As noted, Project Fi gives you money back every month for unused data. It's also two networks. None of the others are two networks.

It's hard to label any one service as "cheaper" than another—it really comes down to what fits your usage patterns. Project Fi's pay-only-for-the-data-you-use policy has the potential for savings, but if you use roughly the same amount of data per month and can perfectly fit yourself into a plan from another prepaid carrier, you have a good chance of saving money elsewhere.

Project Fi is great for people with fluctuating data usage though. Take me for instance: most days, at home and at work, I'm on Wi-Fi, with barely any data usage, but there are those months where I travel a lot, and then my data usage spikes. Project Fi would give me money back for the low-data months, while flexing to a larger plan when during busy months. For a person like me, it's perfect. I don't need data all the time, but when I do need it, I need it to be fast and plentiful.

Still, price isn't the only thing to consider when choosing a network. Fi also has a lot of great features that don't show up in the text/talk/data breakdown. Project Fi's combo Sprint and T-Mobile plan should have better coverage than either Sprint or T-Mobile individually, and the 3G international data will be a big deal for some people. You're also getting the ability to send calls and texts to all your devices—it basically has a (hopefully) non-terrible version of Google Voice built in.

This was a lot to go over and a ton of fine print to read, so if we missed something about your favorite carrier, let us know in the comments. We're still a little light on some of the finer points of Project Fi, but we're eagerly awaiting our e-mails to try out the service first-hand.