AT&T has been fiercely competing with smaller rival T-Mobile U.S. and this weekend, the two compnies announced lower charges for wireless data. Beginning Sunday, AT&T's customers without annual service contracts will pay $65 per month instead of $80 for a plan that includes 2GB LTE wireless data, unlimited talk and text messaging, unlimited international messaging and 50 GB cloud storage. Customers with two smartphones will now pay $90.

Additionally, AT&T recently added unlimited international messaging (text, picture and video) to all Mobile Share Value plans for no additional cost. Unlimited international messaging includes messages sent from the U.S., Puerto Rico and U.S. Virgin Islands to more than 190 countries for text messages and 120 countries for picture & video messages.

And, for a limited time, all new and existing AT&T customers will receive a $100 bill credit for each new qualified line of postpaid wireless service added - whether a smartphone, tablet, feature phone, mobile hotspot or AT&T Wireless Home Phone.

Separately on Friday, T-Mobile said it was doubling to 1GB the amount of LTE wireless data it was providing with its Simple Choice plan, which costs $50 a month, and also includes unlimited talk and domestic and international text messaging.

All four U.S. wireless providers have made price adjustments as they attempt to sustain growth in a market built on stealing growth from competitors.