Nearly a month after Verizon and AT&T doubled the data available on their higher-tier shared plans, both companies have announced similar promotions for their mid-tier and low-tier plans, respectively.

AT&T has boosted data by 50 percent in its $40 and $70 plans, with the former now offering 3GB data instead of 2GB, and the latter now netting you 6GB instead of 4GB. There is no expiration date for this offer, which also include domestic unlimited talk and text, and are available to both new and existing customers. In addition, the company has also extended the "Double the Data" promotion on its higher tier plans to the 15th of this month.

Something worth noting is that AT&T charges a monthly "smartphone access charge" of $40 from those who sign a standard two year contract, and $25 from those who opt for Next, a plan that allows AT&T customers trade in and upgrade their smartphones or tablets every year.

On a similar note, Verizon has increased the data allotment on its $80 and $100 plans. Customers who subscribe to the former, will now get 10GB data per month, up from 6GB that was being offered earlier, while the latter will now get 15GB data per month instead of the previous 10GB. Just like AT&T, Verizon's offer is also available to both new and existing customers, but is apparently limited in time.