T-Mobile rolled out its new no-contract plans without much fanfare over the weekend, with prices starting at $50 for unlimited minutes, unlimited text messages and 500MB of unthrottled data. But the company saved a few surprises for today’s “Uncarrier” event in New York City. Namely, the company officially launched its LTE network in seven markets, and announced April 12 as the day it will finally add the iPhone to its device lineup.

Subscribers in Baltimore, Houston, Kansas City, Las Vegas, Phoenix, San Jose, and Washington DC will be among the first to take advantage of LTE speeds on T-Mobile’s network, which should range between 10 to 20Mbps down and 8 to 12 Mbps up. In areas with low or no-coverage you should still be able to fall back to HSPA+ speeds, which are almost as fast as LTE and better than Verizon’s or even AT&T’s fall back network.

That could be a key advantage for data hungry users on T-Mobile’s network. Moreover, the carrier expects to deliver LTE to 100 million people by the middle of 2013 and 200 million customers nationwide by year's end.

Those who want to take advantage of T-Mobile’s LTE network will be able to choose from a range of high-end devices including the HTC One, Samsung Galaxy S4, Galaxy Note II, BlackBerry Z10, and Apple iPhone 5.

Pre-orders for the latter will kick off April 5 and keeping in line with its new Uncarrier initiative, T-Mobile will let people either pay full price for the device upfront, or spread the cost over the next two years with monthly payments that are explicitly spelled out on their bill. A 16GB iPhone 5 will sell for $99 upfront with 24 monthly payments of $20 — that works out to $579 over two years, $70 less than an unlocked iPhone 5 from Apple.

Since hardware costs are not tied to a contract you are free to switch plans or jump ship at any time, although it's unclear exactly what will happen with a smartphone payment plan in the latter case. During the Q&A session company executives only said you'll have to pay the remaining cost and that there will be a trade-in "fair market credit" to offset the remaining cost in case you want to upgrade to a new phone.

T-Mobile will also be offering the HTC One and BlackBerry Z10 with down payments of $99.

Meanwhile, the previous generation iPhone 4S will be available (sans LTE speeds, naturally) with a down payment of $69.99 and 24 monthly payments of $20, while the iPhone 4 costs $14.99 down with $15 monthly payments over two years totaling $375, a full $75 cheaper than the unsubsidized equivalent.

Devices will be sold locked but you can unlock them once they're paid off.

Apple’s popular handset was an AT&T exclusive in the U.S. since its launch in 2007, with Verizon and Sprint joining the ranks in 2011, followed by smaller regional carriers in the subsequent months. T-Mobile was notably missing from the picture, and this was partly to blame for a widespread subscriber loss. The company is hoping the new addition, along with an updated network and consumer-friendlier plans will win them back.