If you've been waiting for a US-friendly device that ships with Windows Phone 8.1 out of the box, you can stop twiddling your thumbs. T-Mobile is launching Nokia's Lumia 635 (aka the Lumia 630 with LTE) this month for $99 up front at MetroPCS, or $7 per month ($168 total) on a T-Mobile installment plan -- not bad for a phone with Cortana and other features that aren't officially available elsewhere right now. Just when you'll get this spiritual successor to the Lumia 521 will depend on how you like to shop. Your first chance to buy the 635 is on July 5th, when you can tune into the Home Shopping Network to get one on a prepaid Simple Choice plan. After that, you'll have to wait until July 9th to order it online, or July 16th (the 18th for MetroPCS) to find it in a store. It's not the Lumia 930 that many power users crave, but it may fit the bill if you're looking for the cheapest way to get into Microsoft's latest mobile ecosystem.