With some limits
T-Mobile slashed the price of its unlimited data plans, the latest move in the carrier’s three-year long “Uncarrier” marketing campaign. But at the same time, the carrier said it would phase out its less expensive plans that included limited amounts of data.
Under the new “T-Mobile One” plan unveiled on Thursday, customers can get unlimited voice, texting, and data starting at $70 a month for one line, $120 for two lines, $140 for three lines and $20 for additional lines. Unlimited plans had previously started at $95.
New customers who wanted to pay less would have to opt for a prepaid plan, which start at $30 per month, T-Mobile said. Existing customers will be grandfathered and can remain on their current plans.
“A lot of people dab promotionally into these kind of offers,” T-Mobile CEO John Legere said on a call with analysts and reporters. “For T-Mobile, this is it.”
The new plans are subject to several limits, including all streaming video must be viewed at DVD-quality—not in higher resolutions—and customers that use more than 26 GB per line in a month could see their data rates cut to slow speeds.
The new plans will be available starting September 6, T-Mobile said. That is one day before the widely rumored start of pre-orders for the newest iPhones.
Get Data Sheet, Fortune’s technology newsletter.
Rival carrier Sprint s quickly announced its own new, cheaper unlimited plans after T-Mobile’s announcement. The Sprint plans started at only $60 but reduced the quality of music and online games as well as video.
T-Mobile tmus Legere kicked off the Uncarrier strategy three years ago by eliminating two-year contracts. Subsequent moves, including cutting international roaming fees and exempting popular streaming music services from counting in data usage, have helped make T-Mobile the fastest growing mobile carrier in the country.
AT&T’s revamped plans did cut prices dramatically for larger data users.