Virgin Mobile is chasing after T-Mobile customers by offering a $100 credit to anyone who switches from T-Mobile to its own plans, which start at $35 per month. Virgin said all you have to do is pick a phone and then activate it and a new line by May 31. As long as your first payment is before that date, Virgin Mobile will offer a $100 service credit "within the first 30 days of switching" to its network.

Virgin noted its benefits include a monthly plan with unlimited text, data and messaging for $55 per month and that you'll fall back onto its 3G network after using up your limit of 2.5GB of 4G LTE data. It argues that T-Mobile switches you to its 2G EDGE network at the same data cap.

You'll make the move at a cost, however. T-Mobile will offer the Galaxy S4, HTC One and the iPhone 5. Virgin has compelling devices, such as the iPhone 4 and iPhone 4S, even the Galaxy Victory 4G LTE, but you won't see any of those flagship handsets just yet.