RE: Mossberg price
If I were you I would buy it!! It sounds like a tremendous deal. I have a 500 and I couldnt be happier with it. My 500 cost me $215 from academy and it only came with the 28" barrell. My girlfriend ordered me the rifled barrel and scope combo off walmart.com today and that was $150.00.
You should definately buy it. I dont remember how many shells it will hold, I typically use it for dove hunting and I am only allowed three shell capacity due to oklahoma regs.
At that price you could buy it then sell just the two extra barrels on ebay and the shotgun would be free!!