The 4K Bluray Player category is generally in the $200 - $250 price range (still!), here’s a straight-simple player for under $100, and it’s a good one: the LG UP875.
This is a no-frills 4K Bluray player that boots up faster than any I’ve ever seen, is flawless in it’s operation and looks great on the shelf. Plays 4K discs and upscales conventional Blurays to near-4K image quality (also has 1080p Upscaling for DVDs). I’ve read reviews by people complaining about it’s lack of wifi connectivity and lack of apps (such as Hulu, Vudu, etc.). Guess what? Get a Roku box or fork out 39 bucks for a Fire Stick. This is not for anyone who wishes to use his / her bluray player as their primary streaming device.
So what you get here is a 4K disc player that has one job and it does it well. Play movies and recorded material beautifully, and this is reflected in the price, a very fair price. On top of all this, you get the (typical) LG excellence in build quality and a beautiful media appliance, upon which you can rely for a long time to come.
This was something I had not known about, had no plans on buying a 4K player but stumbled upon it while in a Best Buy, with a sale price of $99. Tested on a premium television with 4K discs (and streamed), it’s performance is stellar.