There is no official disk based media for 4k yet. The "mastered in 4k" refers to how they were scanned; they are 1080p disks. I think Netflix offers a tiny bit of content in 4k, but there is no way you can get that on a"somewhat crappy internet connection."
Just don't get a 4k TV.
well what is the difference between a blu ray that is "mastered in 4k" and on that isn't? There many blu-rays in which the movie was transfered to 4k or originally filmed in 4k like the last 2 episodes of the PT and put on blu ray that aren't labeled "mastered in 4k. What's the difference?
Exactly my question. For instance, Battle: Los Angeles (which is a relatively new movie) was, I'm guessing, shot in 4K, has a regular blu-ray, and a new edition seemingly specifically marketed for 4K televisions.