TMobile Plan for mobile hotspot (tethering)

We currently have two services - Sprint SERO for me and TMobile for my wife. I am looking to combine into one provider....maybe TMobile, but I have a question that someone may be able to answer.

The TMobile Store Rep told us that their hotspot was pay as you go, not part of the contract, and could be used when needed and at other times would not be billed.

That sounds great but I can't find anything about that feature on TMobile's website.

My definition of "hotspot" means that I can use my phone as a wireless "hotspot" for several other devices. Is that what he was talking about................or

Does my definition of "hotspot", and most other providers these days, translate to "tethering" in TMobile's jargon and that no such pay as you go feature is offered?

Thanks for any help about my question.

Brad