It seems Microsoft is developing its own SIM cards that will allow Windows 10 devices to access a range of different mobile data networks without the need for a contract. The Verge has noticed that Microsoft has just released a new app called Cellular Data. It explains that the service will allow you to "connect with -- and pay for -- a mobile data plan on your Windows 10 device using only your Microsoft account information. That means no fixed contract and no long term commitments to a mobile network operator."
The app is built to "work solely with specific Windows 10 devices and requires a Microsoft SIM card". However, there's no sign just yet of those SIM cards, so it's unclear where the service will be available and how much its plans will cost. It will, though, clearly all be controlled by Microsoft, so you'll buy a SIM and contract via Windows Store and then use your Microsoft Account for all subsequent dealings.
Exactly which carriers will partner with Microsoft to provide the service is also unclear. We'll have to wait and see.
Image by Simon Yeo under Creative Commons licence