Buy an iPhone from T-Mobile, get half off a second one

T-Mobile has a new deal for you if you're a fan of Apple's iPhones. Starting tomorrow, the magenta carrier will give you half off one iPhone when you purchase two of them. So you pay the full price for one iPhone, and half of it for the second one. That's the theory. In practice, you'll find that the discount will come to you in the form of a prepaid MasterCard. Oh, and you need to add a line for the second device. This line needs to remain active until at least July 15. The deal works with any iPhone model currently sold by T-Mobile, so you can pick and choose from the iPhone 6s Plus,...