Forget paying the crazy amount for a vent booster on Amazon or Walmart! For less than half that price you can build your own and get that unruly hot or cold room under control! Using two 92mm - 12 volt PC fans, a 12 volt psu and a cheap W1209 thermostat. WARNING this does require a larger bed at least 300mmx300mm.
UPDATED 2022-5-20: redesigned housing with easy to push buttons, instead of having to find something to stick down in the holes to setup.