You'll normally pay $50 per month for unlimited talk, texting and data, with the potential for "deprioritized" data (read: it may slow down) if you use more than 23GB per month. There are no commitment. However, you'll get 6 months of service for $1 if you buy an iPhone and sign up -- and those who enlist before July 31st will get a full year of service for the same buck. Also, Virgin is selling the iPhone SE at a starting price of $279 ($379 for 128GB), well under Apple's usual $399. Combine those with perks with Virgin brands (such as a round-trip companion ticket to the UK on Virgin Atlantic) and sales of used devices and it may be tempting to switch over, at least if you're looking for a new iPhone.
We've asked Apple about the extent of its involvement and whether or not more is planned down the line, and we'll let you know if there's anything it can add. Regardless, it's an audacious move. Apple may be playing it safe by partnering with a relatively small carrier like Virgin (Sprint can still count on its own brand and Boost Mobile), but you don't really see providers limiting themselves to one manufacturer -- even fledgling networks like Comcast's Xfinity Mobile have some diversity. Apple and Virgin are clearly betting that many Americans are more interested in a sweet deal on iPhone service than a wide choice of devices.