https://www.cnet.com/news/add-a-4k-blu-ray-player-to-your-home-theater-for-99-99-and-get-blue-planet-ii-free/

Start building your 4K Blu-ray library with this excellent freebie.

I'm on record as saying 4K TVs are kind of pointless, in part because there's so little 4K content to watch and in part because I'm not going to enjoy "Baby Driver" any more in 4K than I did in 1080p.