i researched the hell out of the portable ones and found out that you need the foot pad heater and that makes them cost a little more. very important for extra heat.
$300. national pool wholesalers. ironicaly if you google it's the first one up.
there is one on amazon with a foot pad around $200 don't remember why i went with npw.
although, the one i got also has an ionizer but i don't think it really does anything.
it is the best thing i have ever purchased for myself. my husbanad loves it too.
get one.

Have you purchased a sauna yet? I bought far infrared mat...better than the sauna. The Best!!!!!!!!!!!!!!