I agree on it being taught at BSAC branch level, but i think it should proberably be at Sport Level. As for the cost, i think of the £90 quid i paid £45 covered the Basic and Advanced Course Books plus the BSAC Nitrox Deco tables. Of the remaining £45 the card £12 and the SDC registration £12, so that leaves £21 to cover bottle hire, Nitrox fills and instructores expences.
Which i was quite happy to pay, i also think thats quite good value for money.
The books could be an additional insert into the new Student Study Books.
I'm currently looking at getting a few in my club qualified to instruct it, we will then run it internally. All 3 of us need to do is understudy on a course and i beleve register as a Nitrox instructor (we are already instructors and advanced Nitrox divers).
Depends where you are - my local TDI instructor does it for £50 and no qual dives (cos you don't need them) - BTW this guy is a SERIOUS tekkie, teaches full trimix and is very highly regarded. Goes cheap on basic Nitrox cos he wants everybody on it. £130 totally takes the piss.
It should be one of the first disciplines taught after the rescue quals are done- every now and then I'm obliged to dive air (holidays etc) and I bloody hate it. Rubbish no deco times, if you go into deco it racks up at an astonishing rate, not to mention repetitive diving.