
This is what I'm getting from T-Mobile unlimited (unmetered) hotspot account referenced from this post
here. It's month to month account.
One caveat, stay away from the Huawei B890 4G LTE hub as it has a SIM card issue. T-Mobile's full size SIM doesn't seat properly to register. You need to push the card all the way down, fighting with the internal spring, to make contact. Ended up temporarily jury rigging wire ties and a pvc end cap to keep the card full depressed. :S May just try to trim the SIM card when I get time.