I've been charged multiple times by Comcast for going over. Apple TV 4K with Netflix blows through it in about two weeks with two adults that work full time and rarely stream at most a few hours a day.
According to this article https://www.androidcentral.com/how-much-data-does-streaming-... Netflix 4k is 7.2gb an hour, if you have a 1TB Comcast cap and they're counting that as 1000gb you should be fine for at east 130 hours (giving an allowance for phone/app/os updates and random browsing).
Also, why 4k? Small room, massive display? Many people can not even detect a difference between 1080p and 4k at normal couch distance. https://www.experienceuhd.com/blog/can-human-eye-see-differe...
I've got a 55" 4K at a viewing distance of maybe 6', tops, if you're leaning waaaaay back on the couch, and can only barely tell the difference. A good 1080p source (high bitrate h264 or h265, or a normal ol' 1080p bluray) looks a hell of a lot better than Netflix's 4k. HDR matters a ton more than 4k itself does, as far as how good something looks.
[EDIT] and what really matters is having semi-decent speakers in a somewhat-OK 5.1 layout, with a proper receiver. I'd drop to 720p on the picture before I'd give that up.
Not sure how that is relevant to my comment, but the 2017 nominal median income per capita was $31,786 in the United States. That means even a $650 television is more than a week's gross pay for as much as 40% of the US population.
Most of us are quite content with even 720p too and just because something is 'under $1000' doesn't mean you need to replace a perfectly functional television.