How much would an iPhone 5 cost on T-Mobile with a new contract?

I'm looking into purchasing an iPhone 5 (16GB) and my contract is also up so if I begin a new contract, will an iPhone be cheaper than $629?

Once you finish your contract, you can switch to their new prepaid simple choice plans. T-Mobile does not have any contracts any longer. For the iphone 5, you would pay $149.99 down and each month you would agree to pay $20 more on top of your simple choice plan for the next 2 years. The $20 each month more is to pay off for the cost of the phone for the next 2 years.

So the cost of the iphone 5 = $149.99 + ($20 x 24 months) = $629.99

So after 2 years you would have paid $629.99 for the iphone 5 with T -Mobile.