New data plans from AT&T and Verizon promise cheaper prices the more you share. Which one is the better deal?

One month after Verizon unveiled its , AT&T has taken the wraps off its new , available later next month. The general idea behind each of these two plans is the same: The more data you share, the less money it costs. So which one is the better deal? We compare the two to find out.

Verizon Wireless

On Verizon, each smartphone on your account costs $40, while each basic phone costs $30. Cellular modems and netbooks cost $20, while tablets cost $10. For phones, those prices included unlimited talk time and text messages.

Data plans start at $50 per month for 1GB, which will be shared by all devices on the plan. You can also get 2GB for $60, 4GB for $70, 6GB for $80, 8GB for $90, and 10GB for $100 per month. Above that, you can add 2GB for $10. If you go over your limit, data costs $15 per 1GB.

If you don't need to talk and text, shared data for cellular modems, tablets, netbooks and other devices are available in increments of 4GB for $30, 6GB for $40, 8GB for $50, and 10GB for $60. And if you only need a basic phone, there's also a plan for 300MB of shared data with unlimited talk and text for two phones for $100 per month.

AT&T

On AT&T, pricing is a little more complicated. Again, basic phones cost $30 per month, cellular modems and netbooks are $20, and tablets are $10. But smartphone pricing varies depending on the amount of data you choose. Prices range from $45 if you use 1GB of data, to $35 for 4GB, $35 for 6GB, and $30 for 10, 15, and 20GB plans. Like Verizon, each plan includes unlimited talk time and text messaging for phones.

Data plans start at $40 per month for 1GB, which will be shared by all devices on the plan. There's also 4GB for $70, 6GB for $90, 10GB for $120, 15GB for $160, and 20GB for $200 per month. Additional data costs $15 per 1GB.

Unlike Verizon, it is not yet clear if AT&T offers different pricing for data-only devices like cellular modems, netbooks, and tablets. It is also unclear if different plans will be offered for users who only want to share data among basic phones.

How Do the Plans Stack Up?

Here's what all those numbers boil down to. On Verizon, if you have two smartphones ($40 each per month) and a basic phone ($30), and you select the 4GB monthly plan ($70), your monthly bill will cost $180. As for other devices, if you have one cellular modem ($20 per month) and one tablet ($10), along with a 4GB monthly plan ($30), it will cost $60 per month.

On AT&T, if you have two smartphones ($40 each per month), a basic phone ($30), and select the 4GB monthly plan ($70), you monthly bill will costs the same exact $180 per month as Verizon. Until it becomes clear that AT&T will offer different pricing for data-only plans, one cellular modem ($20 per month) and one tablet ($10), along with a 4GB monthly plan ($70) will cost $100 per month.

Here's another example. On Verizon, if you have two smartphones ($40 each per month) and a tablet ($10), and you select the 6GB plan ($80), your monthly bill will cost $170. AT&T works out to the same price, except you'll be paying $35 per each smartphone, $10 for the tablet, and $90 for your 6GB of data.

On Verizon, data tends to cost less, but on AT&T, you'll be paying less per each smartphone if you choose a plan that uses 6GB of data or more, so it's really a tossup. On the other hand, until we know that AT&T will offer different pricing for data-only or basic phone-only plans, Verizon is your better bet there.

Full plan details are available directly from AT&T and Verizon. Use those, along with results from our testing for the Fastest Mobile Networks 2012, to help you decide.