I would be real careful with public purchasing sites;Ebay/Craigslist ect.Lots of scams out there.
As to your original question - YES - almost anything is cheaper in the winter. Tractors, motorcycles, boats... Guys are trying to get money for taxes, Christmas gifts, or whatever and things are much more negotiable.
For example Im looking at a bx25 with 50 hours on it this week for 13500, to me that looks like a **** of a deal right?
I know there is crap on there for 2500 they are the scammers.