are you saying that there are many teachers here who are teaching iron palm? It's not something I've paid much attention to, I kinda assumed it's not taught much, and where it is, it's probably done in small private groups for the senior-most students and disciples. Probably not made available for the average student.
So...I suspect private instruction, once you become well-established with a good teacher who has decided he can trust you (could take years) then you get private instruction and you might need to pay extra for it.
that's just my guess, tho.
where are you, what's your background, with whom are you currently training?