A leaked document from AT&T shows that the company is planning to offer only unlimited and per-message texting plans starting August 21, according to Engadget. The only available plans will be $20 for an individual unlimited messaging plan or $30 for a family unlimited messaging plan; customers without one of those plans will pay 20¢ per text and 30¢ per multimedia message.

AT&T quietly axed two of its texting tiers in January of this year already, doing away with the $15/1,500 and $5/200 messages plans. In their place, the company offered one $10/1,000 messages tier, as well as the unlimited plan.

AT&T and other carriers have previously faced backlash over increasing texting prices and recently took measures to control data use on their network. While we've pointed out before that text messages do ride carrier networks in a different, higher-priority way from standard data, AT&T still likely makes quite a bit more money from them.

From regular data plans, such as AT&T's $25 for 2GB data plan, the company pulls in about a millionth of a cent per byte. At that rate, a single 140-byte message would cost about 0.0002¢, meaning customers would have to send 11 million text messages to make AT&T's $20 texting plan a money-losing proposition for the telecom giant. The average American teenager—the most avid texting demographic—sends an average of 3,339 texts per month, or 58¢ worth of regular data charges. The other $19.42, you're paying for the messages to send and arrive reliably and immediately.

"What we’re seeing is that the vast majority of our messaging customers prefer unlimited plans," an AT&T spokesperson tells Ars, confirming the plans and noting that text messaging growth is "stronger than ever." Only new customers and those resigning contracts will be subject to the new unlimited texting charges.