T-mobile and Apple (iPhone 5)?

I read some articles saying that T-mobile will start selling apple products. I want to get the iPhone 5 and the regular starting price is $199 for 16GB, but instead T-mobile is selling it for $649. Can I buy the iPhone 5 elsewhere and bring it to T-mobile?

T-Mobile is getting rid of their contract prices

you could buy it directly from Apple, but it will cost you the same amount ($649)
if you buy it under contract with AT&T or another wireless company, you can unlock it and use it, but if you don't keep paying that other company, they will blacklist the phone and it will stop working.

Yes, T-Mobile and Apple have reached a deal and T-Mobile will soon start carrying Apple products.

No, the regular starting price for the iPhone 5 is NOT $199. That is the subsidized price that other carriers offer- they pay a large portion of the cost of the phone while you agree to an expensive monthly contract where they get what they paid for the phone back.

It is not yet known what T-Mobile will sell the products for, but rumor does have it that they will not be subsidized. This will make them more expensive at first, but actually less expensive in the long run.

Yes, you can purchase an iPhone 5 elsewhere and bring it to T-Mobile. But you will not be purchasing it for $199- it will cost a lot more. You would have to purchase the unlocked version which is much more expensive. Also note that non-TMobile branded phones will not work as smoothly on the network as ones that are T-Mobile branded.