First, a few things to keep in mind:
— The price you pay for mobile service should be only one factor. In my travels, I was more likely to get high-speed data service with AT&T and Verizon, especially in rural areas. T-Mobile has improved in many cities. Sprint is still catching up. A plan with a large data allotment won't mean much if you can't use it. Also, if you travel a lot, only T-Mobile offers free data roaming outside the U.S.
— The prices I compare here are for voice, text and data services only and do not include the cost of the phone. Taxes and fees are also extra, as well as one-time charges to activate service.
— The best deals tend to require that you buy a phone at full price or bring your own phone. Buying a phone means paying $600 or more up front for a high-end phone or spreading that out in monthly installments. With Verizon, you must participate in its Edge installment plan to qualify. Rates for voice, text and data services go up if you buy a subsidized phone for about $200 with a two-year contract. For a high-end phone, you're still typically better off accepting the subsidies and paying the higher service rates if you upgrade right at the two-year mark.
Verizon and Sprint have great prices for individuals, who typically need 2 gigabytes of data per month. Unsubsidized plans are available for $50 a month and include unlimited calls and texts.
With AT&T, you pay $65. T-Mobile doesn't have a 2 GB plan. It offers 1 GB for $50 and 3 GB for $60.
With Verizon, avoid its flagship More Everything plan if you're an individual needing 2 gigabytes. Verizon offers single-line 2 GB plans through More, but for $80. Ask for the special plan for individuals, which is just called Single Line Plan.
But if you need something other than 2 GB or have tablets to add with Verizon, you're stuck with More. And this special plan is billed as promotional, so Verizon might yank it anytime.
Verizon and Sprint are also the best for subsidized plans with 2 GB — $60 with Verizon and $65 with Sprint. AT&T's costs $80. T-Mobile no longer offers subsidized phones.
Sprint and T-Mobile are the only carriers still offering unlimited data to new customers. Sprint's is $60 for an individual, while T-Mobile's is $80. Both plans are unsubsidized. Sprint's deal is particularly good, as it's just $10 more than the 2 GB plan, though make sure you live where Sprint has good service.
Technically, all T-Mobile plans are unlimited, but the company reduces your speeds greatly after you hit the allotment. The unlimited plan offers unlimited data at 4G LTE speeds, the fastest available today.