The Big Four carriers’ shell-game-like pricing practices have become so convoluted, you almost need an advanced degree in math to decipher them. They continually shift prices up or down on their cell-phone plans according to the number of phone lines you need and the amount of data you're purchasing. They further complicate matters with “special” short-term offers to lure customers from rivals.

We’ve decided to omit most of these specials when we evaluate offers because of their extremely short life span and their fragility—the benefits often vaporize when a customer buys a new phone or makes other changes. Here we take a look at AT&T's Next on Mobile Share Advantage; Sprint's Family Shared Plan and Unlimited Plan; T-Mobile's One; and Verizon's Simple Plans.

The good news: Some of the wilder, very short-term pricing deals seems to have abated—at least for now. And in some ways, comparison shopping has become a tiny bit less onerous.

If you're contemplating a move to another carrier, we’ve already done the math for you in the tables below to help you find the best deal. And to make sure your needs are covered, we’ve presented the service-cost breakdowns for one to five family members for light, medium, and heavy data service. All you need to do is figure out how much data your family needs; check our cell phones and services buying guide for tips for choosing a plan.

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No-Contract Plans

One bright note from the “cell war” chaos between the Big Four carriers, where more than 80 percent of our survey responders get their cell service, is the appearance of no-contract plans. No-contract plans separate the purchase of the phone from the service charges. This effectively gives you an interest-free loan you can pay off over about two years. When you’ve paid off the phone, your monthly bill goes down accordingly. And there are no termination fees; if you want to leave the carrier, you just pay any remaining balance on the phone.

AT&T Next on Mobile Share Advantage

AT&T has finally dropped the variable-rate access fees it was charging for phones accessing its sharable data plans. And that's a good thing. The company used to charge customers less per phone ($15 instead of $25) when they bought more than 5GB of sharable data. And that could have mislead consumers into paying more—not less—when they tried to save money by cutting back on data. Now the company charges a flat $20 per phone. Unfortunately for AT&T, this makes it easier for consumers to realize that this company's rates are among the highest.

Sprint Family Shared Plan and Unlimited Plan

For customers with traditional cell-phone plans, Sprint earned some of the worst customer-satisfaction scores in a survey completed by 100,000 Consumer Reports subscribers. The study asked about customer support, value, voice quality and connection, texting, internet reliability, and data service. (AT&T fared no better in the survey, and Verizon did only slightly better.)

But Sprint's Unlimited Freedom plan offer seems like a tempting deal for heavy, and even moderate, data users: unlimited talk, text, streaming video, gaming, and music at prices starting at $65 for the first line, $110 for two lines, and $35 for each one after that (up to 10 lines). The company has also dropped the access fees for this deal. Those prices are comparable to what the other carriers usually charge for 4 to 6GB of 4G data per phone.

Sounds too good to be true? It is—especially if you’re heavily into gaming or streaming high-quality video. Though 4G LTE data connections promise download speeds of 5 megabits per second (mbps) or more, in the fine print of this offer Sprint says it’s trimming download speeds for music and video streams to a maximum of 500 kilobits per second (kbps). That’s 2G, a good data speed in 2007, when the iPhone was introduced, but rather slow in today’s higher-bit-rate, higher-definition world.

Music streamers may not notice a quality drop, because most music-streaming rates—even for Pandora’s premium service—rarely go much beyond 300kbps. But if you’re planning to watch an HD episode of "Game of Thrones" on your new Samsung Galaxy S7 smartphone, you’re probably going to be disappointed.

For internet gamers, the limit will be 3G speed (2mbps), which could mean fatal reaction times in fast-paced racing games like Asphalt.

T-Mobile One

T-Mobile doesn't offer data-sharing cell-phone plans. You have to purchase data separately for each phone in your household.

Recently, the carrier dropped its Simple Choice plans. These plans provided unlimited voice calls and text, among other freebies, and also allowed you to tweak your phone bill to choose how much data you fed each phone (3GB, 6GB, etc.). They have been replaced by T-Mobile One plans, which charge one fee for unlimited data, voice minutes, and texts. The price breakdown goes like this: $70 for the first line, $50 for the second line, and lines three through eight are $20 each.

These plans are more expensive than the Simple Choice plans, which didn't count streams against your data allowance from prime music and video content providers such as Spotify and Netflix. But the new rates are still better than the high-end data plans from Verizon and AT&T, and on par with the unlimited plan from Sprint.

Verizon Simple Plans

Big Red keeps things simple: It charges a flat $20 for every phone tapping into its sharable data plans—like AT&T. And also like AT&T, its rates are relatively high. For a "limited-time" promotion, Verizon is adding a bonus of 2GB of data to sharable data plans 8GB or larger. But it applies only to customers buying new phones, and it could be rescinded at any time.

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