T-Mobile has announced what it calls a "truly unlimited" 4G data plan, with "no data caps, speed limits or bill shock."
The new plan costs $20 when added to a "Value" voice and text plan or $30 per month when added to a "Classic" voice and text plan. This means that a truly unlimited plan -- we're talking unlimited voice, text and 4G data -- costs $89.99.
For comparison, AT&T's most generous data plan is 20 GB (which you can share across up to 10 devices), and that costs $200 a month when you add unlimited text and calls. Sprint's "unlimited" data plan, coupled with unlimited text and calls, costs $110.
One catch is that T-Mobile's new data plans are only for smartphones, not tablets or data sticks, and mobile hotspots are also not included in the deal.
Furthermore, unlike AT&T or Verizon, T-Mobile currently doesn't offer LTE connectivity (though its HSPA+ connectivity currently covers most of the U.S.) or the iPhone. But LTE is coming to T-Mobile in 2013, and hopefully the new data plans will still be valid by then.
The new T-Mobile data packages will become available to new and existing customers on Sept. 5.