No. 2 domestic carrier AT&T (NYSE:T) has launched a new prepaid brand, Aio Wireless, that will target "value-conscious" consumers looking for wireless service without annual contracts, and will offer unlimited talk/text/data plans.

The service from the AT&T subsidiary will launch today in select stores in Houston, Orlando, and Tampa, with new markets expected to roll out over the next year.

Aio's service plans will range from $35 to $70 per month, which may vary by region. Aio will also offer a full lineup of devices similar to what's available in AT&T's portfolio, including Apple iPhones and popular Androids.

The focus on prepaid may be a response to T-Mobile's recent un-carrier initiatives. AT&T said it doesn't expect the launch of Aio to change its January guidance.