Not to be outdone by AT&T, Sprint and Verizon have now announced they are also going to double the data for users on shared mobile plans, at no extra cost. What's more, both carriers are bringing the promotion to family and business customers alike, making the news all the better. With Sprint, for example, you can get 120GB maximum for $225 per month on a family plan, while business accounts will receive up to 200GB for $330 -- on the former, there's also the $130 option, which lets you share 60GB between lines. Similarly, Verizon is set to double the data amount on its 20GB, 30GB, 40GB and 50GB More Everything plans; the 12GB and 16GB are making the jump as well, but only to 15GB and 30GB, respectively. Verizon's promo is kicking off tomorrow, with Sprint following suit the day after. But be sure to act fast, since the networks will only be offering this through the end of October.