AT&T's new Mobile Share plans could put pressure on the other carriers. AT&T Sunday launched new Mobile Share plans that offer new and existing customers a significant drop in their wireless bills. 

The new plans start at $130 per month for two lines with 10 GB of data and unlimited talk and text. With the new plans, the carrier has dropped the monthly device charge to $15, regardless of the type of device. With other plans, smartphones incurred a $40 monthly charge, while basic messaging and feature phones were $20 per month.

The plans are available to new and existing customers regardless of whether they are on a contract. 

The new plans put AT&T offerings more in line with T-Mobile's family plans, which start at $120 for two lines depending on the amount and speed of data the customer selects. 

Aside from undercutting T-Mobile's plans, AT&T's latest pricing structure could have Verizon Wireless looking over its shoulder. Verizon's Share Everything plans start at 2 GB of data for $60 with a $40 per-month charge for a smartphone. A plan with two smartphones and 10 GB of data like the one AT&T is now offering would run currently run $180 on Verizon. 

Not to be left out of the game, Sprint recently unveiled "Framily" plans, which start at $55 for unlimited talk, text and 1GB of data. From there, the plans decrease as more individuals are added to the plan, eventually dropping to $25 per month when a single plan hits 7 devices. Because each account can be billed separately, customers can choose who is in their group. For $20 per month, per line, Framily members can buy up to unlimited data plus get a new phone every year. 

AT&T's moves signal an increasingly competitive market that appears to have been at least partly the work of T-Mobile's aggressive "Un-Carrier" strategy. Some have argued that T-Mobile has done too good a job of shaking up the market for regulators to approve a rumored merger with Sprint. Regulators rejected AT&T's bid for T-Mobile on anti-competitive worries.  

Shares of AT&T Monday were down about a half percent to $33.18 in early trading.