I have no 4K TV and yet I got a Chromecast Ultra via the trustworthy eBay. I lowballed the seller and we met in the middle. That's the only way to go.
Officially the Chromecast is selling for $35 and the Chromecast Ultra is fetching $69.
I don't know much about the technology, I think that kind of goes without saying as I am going through life without knowing anything basically.
I have tried that with Vudu watching what else America Ultra. Both the video and audio are very good indeed. Youtube casting is equally impressive. I cast Youtube from my Mac desktop/Chrome browser as well as via iPhone's YouTube app.
Casting is a no brainer.
But setting up the Chromecast hardware needs a bit of work as I needed to install the Google Home App first. I didn't know about it as I thought it was 100% plug and play. Not so. I can't remember exactly but a year ago, my LG was able to do casting without nothing installed both from Youtube and Netflix. Then kind of all of a sudden the cast doesn't work at all. So I always got the impression the cast just works. So when I plugged in the CU into the HDMI, I thought it just works but neither the iPhone nor the Chrome on desktop would see the device. I thought the seller sent me a dud, which is actually quite rare. Knowing that I don't know nothing so I looked up the Chromecast hardware and bang installing the Home app. I must have read it before when I did my research but since my experience before I just thought it would just work. Oh well something something happened, which I didn't know better.
The video and audio exceed my expectation.