You'd be paying a premium because the Cimarron was Schwinn's top of the line mountain bike. This model has a big following on bikeforums. Here's the thread if you want to learn more (this one looks ~1986):
http://www.bikeforums.net/classic-vi...-cimarron.html
So I don't think the price is as crazy as others have stated.
Pic assist:
But if all you want is a commuter, you shouldn't have a problem finding a decent mtb for less than $100. If you post where you live and how tall you are, perhaps we could give you craigslist suggestions.