Before I go any further, I want to clarify something that seems to be causing some confusion out there. Yes, you can run Windows 10 on a Raspberry Pi, but it's not the Windows 10 that most people are thinking about when they think "Windows 10," with a Start Menu and such. This is Windows 10 IoT core, which is a different thing. Yes, you can do lots with it, but you're going to need to do some learning (here you go, baby birds, go feed yourselves).
So, cheap Windows 10 computers. Yes, they exist. And yes, they're pretty good.
But they have limitations.
In my experience many people love the idea of a cheap computer right up until they get it home and start using it, then the restrictions start to become annoying. These computers are not designed for Office, Photoshop, or Crysis. They are, however, great for browsing the web, using social media, or streaming content.
This is a pocket-sized computer powered by a 64-bit quad-core Intel Atom Z3735F processor running at 1.33GHz, 2 GB of DDR3 1600 RAM, 32 GB of SSD flash storage, and Intel HD Graphics 5500.
All for $99 (less if you shop around).
Yes, you can buy a Windows 10-powered computer for $99
Alternatively, there's something like the Dell Inspiron i3050-3000BLK. At $155 this is a bit pricier, but you do get a 2.41 GHz dual-core Intel Celeron J1800 processor, and the ability to upgrade the RAM from the weaksauce 2GB to a more robust 8GB, if you want.