I don't know what area you're in, but up here it's pretty common to see 6 nearly new tires selling cheap on Craigslist or eBay (Kijiji up here) Classifieds.
Folks buy a new dually in the summer time and don't think about snow till it hits, then they realize the "M&S" radials it came with are no good for mud or snow.
They sell the 'old' tires off cheap to subsidize the cost of proper new tires.
I bought 6 Michelin's with about 6k miles on them for $600 last year.
Have a look around your area, you never know.
Ted 'n' Laurie, plus Jackson (aka Deputy Dog, the Parson Russell Terrier 'fur kid') and, Rylie (who crossed the Rainbow Bridge June 14, 2012).