I would compare the price with other similar workshops in Australia - it's not really relevant to compare with the US where all fabric, quilting supplies etc are a lot cheaper than here in the UK or in Oz... Having said that, it does sound like a lot but perhaps with that number of instructors, you'll get a lot of one-on-one? I'd want to ask more questions as to what is actually involved before committing to that much money.
Having said there's no point in comparing prices in another country, I WILL say that I recently did a one day advanced FMQ workshop with around 7 other ladies given by Ferret who is an English award-winning quilter, (certainly in the same bracket as Sharon Schambers and co) and that cost me £32 which equates to $41 Australian... :-D