(AP)

AT&T announced Thursday that it will offer an unlimited data plan to everyone, following a similar move by Verizon earlier this week.

Previously, only DirecTV subscribers were allowed to sign up for AT&T's unlimited plan. Now anyone can.

A single line costs $100 per month and each additional line costs $40 more per month. You can add a fourth line for free, bringing the cost to $180 per month for four lines.

The plan doesn't include hotspot data. You'll have to pay extra if you want to tether your phone's connection to another device.

Like other "unlimited" plans, AT&T says it may slow down your speeds after you use 22 GB in a billing period during times of high network congestion.

As we've written before, there's no such thing as truly unlimited data. There's always a cap, and in some cases your speeds may be slowed down if you hit a certain limit. All four major carriers have similar policies. Still, you can use as much data as you want without being charged extra.

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