Just a few weeks ago, Microsoft began rolling out an update to the built in Windows Store that rebranded the app as "Microsoft Store." At the time, outside of the rebrand, not much else had changed within the app, making the rebrand slightly odd. As it turns out, Microsoft is planning to sell more than just digital content via the Store in the near future.
Spotted by WalkingCat on Twitter, typing a command into the Windows 10 Run dialog box (WIN + R) will bring you to a currently hidden dedicated Surface area within the Microsoft Store app that allows you to buy Surface hardware. It works much like any other area of the Store, including a buy button and Microsoft account integration with Windows Hello support for purchases.
While this function isn't public on the Store front just yet, it's definitely clear that Microsoft wants to unify its purchasing experience on Windows 10. Bringing hardware to the Microsoft Store app is the next step in its One Store vision, where a user can come to the Store and buy anything they want, outside of music of course.
There's no ETA for when this will be ready for the public, but if you want to give it a try now, you can type the following into the Run dialog box: ms-windows-store://navigatetopage/?PageName=ShopSurface