AT&T has become the latest wireless carrier to conjure up a new unlimited data plan, following the lead of Verizon over the weekend and T-Mobile a few days ago.

The nation's second largest wireless provider resurrected its unlimited data plan a little over a year ago but with one big catch - you had to also subscribe to AT&T's cable or satellite TV service just to qualify for the unlimited data plan.

The new unlimited plan, which goes live on Friday for all consumer and business postpaid customers, eliminates the need for a concurrent pay-TV subscription.

AT&T is offering four lines of service with unlimited talk, text and data* for $180 per month (after 22GB of data usage, connection speeds may be slowed during periods of network congestion, AT&T says). That works out to $100 for the first line, $40 for the second line and $40 for the third line. The fourth line is technically free, thus arriving at the monthly rate of $180 for all four lines.

Additional lines can be added past four at $40 each. Business users can also take advantage of their additional corporate discount, AT&T said.

Other noteworthy tidbits include the option to talk, text and use data in Canada and Mexico with no roaming charges by enabling the Roam North America feature at no extra cost and the ability to send unlimited texts to over 120 countries.

Critically, tethering and mobile hotspot use is prohibited (expect for Connected Cars), a surprising omission given the cost of entry.

Sprint, the nation's fourth largest carrier, has also modified its unlimited plan and is now offering unlimited talk, text and data* for $50 a month for one line or up to four lines for just $90 per month. This bundle also comes with 10GB of mobile hotspot usage per line and a free upgrade to HD-quality video.

Furthermore, those that turn in a qualifying device when switching to Sprint can get an iPhone 7 free for 18 months.