https://www.cnet.com/news/t-mobile-announces-50-prepaid-unlimited-data-plan-following-at-t-and-verizon/

You can find this on the T-Mobile prepaid website.

There are some caveats. Video streaming is typically at 480p resolution (not HD), and T-Mobile may throttle your speeds if you use more than 50GB a month (which is a lot of data to use). Tethering is also at a max of 3G speeds instead of 4G/LTE.