If you've been on the same unlimited AT&T data plan for years, your bill may be getting more expensive.

Enlarge Image

AT&T is reportedly raising the price of its grandfathered unlimited data plans to $45 per month starting July 2018, according to a company support page  (via MacRumors). (That page seems to have subsequently been removed from AT&T's site.)

These unlimited data plans keep getting more expensive. Even if you snagged an affordable rate years ago, you may still have to pay more. AT&T's unlimited data plans used to be $30 a month in 2015, before it was raised to $35 in 2016, then again to $40 in 2017.

Despite the hike, $45 a month may be your best option on AT&T. Current AT&T unlimited data plans can cost either $65 or $80 a month for one line. It's cheaper if you add more people though, at $160/$190 a month for four lines (that's $40/$48 per line).

Meanwhile, Sprint just kicked off an insanely low $15-a-month unlimited data promo.

AT&T didn't immediately respond to a request for comment.

Tech Culture: From film and television to social media and games, here's your place for the lighter side of tech. 

The Smartest Stuff: Innovators are thinking up new ways to make you, and the things around you, smarter.