(this is copied from the blog post I just made: https://blog.getpaint.net/2017/09/29/paint-net-is-now-available-on-the-windows-store/ )
Version 4.0.18, which I just announced, is now available on the Windows Store! The standard price is currently $8.99, but I’ve put it on sale for $5.99 $4.99 until the end of October. You can also make use of the 30-day free trial to get started.
(It may take a little bit of time before you can search for Paint.NET on the Windows Store. I