Families with light to moderate data usage are the most likely candidates to find value in the shared-data buckets that AT&T and Verizon offer, says Maggie Reardon, senior writer at CNET.com and author of the site's Ask Maggie column. If one person tends to burn through a couple of gigabytes or more on her own each month, you may want to have her sign up for her own plan, or consider Sprint's unlimited family data plan.
Validas determined that a "well-connected" family of four with typical usage -- including three smartphones, one standard (or feature) phone, two tablets and a mobile hot spot -- would spend about $310 per month with Verizon's Share Everything plan. The tally for a family of four using smart phones with the Sprint Simply Everything family plan, which includes unlimited voice, text and data, starts at $390. But if you keep voice minutes to 1,500 per month, the Sprint price starts at $190 for a family of four.
A family of four who talk and text a lot could spend as little as $120 with T-Mobile's Unlimited Value-Plus plan, in which you bring your own compatible phones to the carrier. The plan includes unlimited text messaging, calling and data, but T-Mobile slows data speeds once you pass a 2GB threshold. For $180, you get 5GB of full-speed data.
If you prefer unlimited data usage (meaning data speeds won't be reduced once you reach a certain limit) with a big carrier, your only option is a Sprint plan. The all-you-can-eat Sprint Simply Everything plan runs $110 per month for unlimited calling, texting and data. If you're not a big talker, drop to 450 minutes per month for $80. For $70 per month, no-contract carrier MetroPCS provides unlimited talking, texting and 4G LTE data (meaning it operates on the speediest, most advanced data network), and it doesn't slow data speeds. On the $60 plan, you get 5GB of data before speeds drop.
Use your phone mostly for calling and texting? T-Mobile offers unlimited text messages and calls with no data service for $60 with a T-Mobile Classic Unlimited Talk + Text plan. Bring your own phone and pay $50 per month with a Value plan ($55 per month if you want to add 200MB of full-speed data).
If you're willing to go with a prepaid carrier, you can get unlimited calling, texting and, often, at least 2GB of full-speed data with a smartphone for $55 or less. With Boost Mobile, which runs on Sprint's network, you start with a $55-per-month plan for an Android phone with unlimited talking, texting and data. If you make on-time payments for 18 months, the price drops to $40. Straight Talk offers unlimited calling, texting and data for $45. The monthly savings on prepaid service usually makes up for the higher premium you'll pay to buy an unsubsidized phone.
For someone who pulls the phone out only in emergencies or to talk less than an hour per month, prepaid is the way to go. The T-Mobile Prepaid Pay As You Go plan gives you 1,000 minutes for $100, and you can use them for a year. Tracfone Monthly Value plans range from $10 per month for 50 minutes to $30 per month for 200 minutes.