Currently, carriers are changing their plans almost daily, and they've become very difficult to navigate and figure out which one is actually the cheapest. So what we are doing is each month, showing you which carrier has the best plan for a single line, family plan and off-contract (or prepaid). To help you pick out the best carrier plan for you. Let's lay some things out first. For a single line we'll be looking at between 2 and 4GB of data, unless they have unlimited data. And for family plans it'll be 4 lines, with around 8-12GB of data.
With Verizon's family plans, you are paying $40 for each smartphone, and $10 for each tablet, just to connect to their network. If we look at their 8GB plan, that's $85, on top of the monthly access fee. So if you have 4 smartphones and 8GB of data, that works out to about $245/month. With Edge you can get $25 off per line, but you are also paying extra for your phone as you're essentially leasing it. So it doesn't really work out any cheaper. And in some cases it's actually more.
On the single line side, you can get 2GB of data for just $75, or 1GB for $60. With Edge, it'll be $15 off, but similar to the family plan, that doesn't always make it cheaper.
Verizon prepaid is what we'll do for off-contract here seeing as Verizon's off-contract prices on postpaid are the same. With Verizon prepaid your options aren't all that great. They only offer one plan and that's $45/month for unlimited talk and text along with 1GB of data.
AT&T basically has one style of plans. So we'll be looking at family plans together with single line plans. For Family plans we'll be looking at the 10GB data bucket. So with 4 lines at $40 each, and 10GB of data at $100, that equals about $260 per month for four lines. Since AT&T doesn't have an 8GB plan, it's kinda tough to really compare it to Verizon. For a single line, it'll be $40 for the line, and then $40 for 3GB of data. Which means you're paying $80/month.
Moving to off-contract. If you do AT&T Next or off-contract, it'll be $25/month on the 300MB-6GB plans and $15/month on the 10GB+ plans. So let's go with 3GB here. That'll be $25/month for the line and $40 for the data, coming out to $65.
Sprint has some interesting plans. For family plans there's the Family Share plan. Which you can get 4 lines, with 20GB of data and unlimited talk and text for $100/month. That's actually a really good deal, considering what other carriers charge.
When we go to single line plans, Sprint offers unlimited everything for $60/month (although if you buy an iPhone 6 or 6 Plus it'll be $50/month).
On Prepaid, Sprint has a ton of options for you. But we'll leave Boost Mobile and Virgin Mobile out. For $35/month you can get 1GB of data, $45/month gets you 3GB of data and $55/month gets you 6GB of data. No throttling here, you are basically cut off when you hit your cap. These all come with unlimited data too.
With T-Mobile, you can customize your family plan a bit more than the others. With AT&T and Verizon we did 8-10GB of data, so we'll do that with T-Mobile as well as compare it to the 20GB that Sprint has. For 4 lines and 10GB of data (that's 2.5GB for each line) that comes out to $100/month. But you also have to include the price you're paying per month for your phone. Which can be as high as $27, so with phones included, it could be as expensive as $200/month. For 20GB of data, we're looking at $180, plus around $100 for the EIP on smartphones, so that's about $280/month.
Single lines at T-Mobile are pretty straight forward, compared to the others. You've got your EIP which can be as high as $27 each month. Then you can get 1GB of data for just $50, 3GB for $60, 5GB for $70 or unlimited for $80. So if you want truly unlimited, you're looking at about $107.
For prepaid, we're looking at 1GB for $40/month, 3GB for $50/month and 5GB for $60/month. Now this is prepaid so you're buying your phone at full price, which means no EIP.
Comparing them all
First thing you need to do is check coverage before deciding on any of these plans. But if coverage wasn't an issue, I'd say that Sprint has the best plans for prepaid/off-contract, single line and family plans. But please check coverage first, as not all carriers have the same coverage in the same areas.