AT&T announced its version of a data sharing plan as well in August.

Before the Share Everything plan was launched, the most cost-conscious customers could buy a $70 a month smartphone plan. "Verizon slammed the door on these people and hiked the minimum plan price to $90," said Tero Kuittinen, an analyst at Alekstra Oy, told the .

Even so, the overall pricing environment in the wireless industry has been steady, and no single carrier has been irrational with pricing, added Colby Synesael, an analyst at Cowen & Co.

Growth rates on wireless services can't last forever, he warned. "There's a finite amount of consumer discretionary money," Synesael said.

Analysts wouldn't suggest a maximum price that average subscribers would be willing to pay each month, but they said a ceiling exists.