T-Mobile on Wednesday announced a new set of low-cost business plans and some deal sweeteners for consumers at its "Uncarrier 9.0" event.

The centerpiece of the event was a new set of wireless plans, primarily for small and medium businesses. They're inexpensive and simple, requiring no negotiation, which T-Mobile CEO John Legere said was a major drawback of existing business plans.

"70 percent of business customers say [the buying process] isn't transparent enough ... the best price is the only price, for everyone," he said.

Here's how it goes: Businesses must order at least 10 lines. The first 10 lines cost $16 each with unlimited talk, text, and 1GB of data per line. Go above 10 lines, and you pay $15 each; above 1,000 lines, they become $10 each. Tablets and hotspots are $10/month each.

Additional data can be added per-line or pooled. Per-line data costs $10 per 2GB or $30 for unlimited. T-Mobile charges by the gigabyte for pooled data for businesses: $4.75 each for the first 500 GB, $4.50 after 500 GB, and then $4.25 after 1 TB. There are no overages, and businesses are just charged by the gigabyte of use.

Business customers will also get a GoDaddy domain, a mobile-optimized website, and an email mailbox provided by Microsoft, on their own domain.

Legere pointed out that his company is reaping only $4 billion of the $83 billion in business wireless sales right now, so any business customers it gains will be straight out of the pockets of AT&T and Verizon Wireless.

Legere also threw in some sweeteners for consumers, who are almost all of T-Mobile's current base. The company will pay up to $650 per line in switching costs from another carrier, which now includes paying off leases and phone payment plans such as AT&T Next and Verizon Edge, he said.

Families of new business customers will be able to sign up for personal lines with the first line discounted from $50 to $30/month plus data, he said.

Existing T-Mobile customers, meanwhile, will see any promotional plan they're on made permanent, with a guarantee that rates will only go down, not up. The exception is unlimited-data subscribers, who will only get the guarantee for two years.

"Unlimited is a world in and of itself; I can't pretend to tell you the ten-year view on Unlimited," Legere said.

More Coverage Coming
Coverage is one of the major complaints that potential business customers have about T-Mobile. One small businessperson at the event complained that his T-Mobile Samsung Galaxy S3 had problems with in-building reception.

Legere acknowledged that T-Mobile is still expanding its coverage. "We have some rural edge, some in-building penetration that is still stuff we're working on," he said.

The carrier's main problem is that it's primarily on higher-band spectrum than AT&T or Verizon, and while that's ideal for carrying fast data, it's not very good at covering distances or penetrating building walls.

Legere said T-Mobile will lean hard into next year's 600Mhz "incentive auction," but that spectrum will probably be built out between 2017 and 2020. Legere has been lobbying the FCC to make sure the auction rules set aside some spectrum for companies other than AT&T and Verizon Wireless.

"We will get low-band spectrum in the incentive auction," he said. "You're going to have to make sure ... nobody can get more than 20Mhz and the small player gets a chance."

The company will also start installing in-building systems based on 5Ghz "LTE-U" technology next year, it has said.

For now, coverage hopes rest on T-Mobile's 700Mhz spectrum, which covers 190 million people. That spectrum is much more like the airwaves AT&T and Verizon use to penetrate buildings. While the carrier has been rolling that out across the country, it's been slowed in some areas—like New York—because it requires existing TV stations on Channel 51 to get out of the way.

Where 700Mhz has been rolled out, such as in Cleveland, Minneapolis, and Washington, it's resulted in "huge improvements" in in-building coverage and "dramatic" rural expansion, T-Mobile CTO Neville Ray said. (You can find a great 700Mhz map and explanation here.)

"Every month that goes by we're adding more and more markets," Ray said. "We've had great opportunity to coexist with Channel 51 incumbents and we're going to keep driving very hard."