Spas 12's normally run around 800 to 1200 depending on the type of stock (Fixed / folding) and mag extensions etc.
Again, Chris Cooney's website is the best source of information about the SPAS. Check out some SPAS ads at http://chris.cc/spasads.htm
and a buyer's guide at http://chris.cc/spasbuy.htm
Also take a look at www.gunsamerica.com
under Franchi Shotguns for more ads.