You either buy new or buy used and expect a hefty discount. New get's a warranty and piece of mind that PROBABLY noone else messed it up.
I've got 4 new to me saws this last year and a bit.
Efco 3600, 16", brand new w/ warranty and 2 chains - $50 from NT. Couldn't pass up a new saw for $50.
John Deere CS62 I won here, very lightly used - litefoot's raffles saw #2
Stihl 660 BOUGHT ON EBAY
Stihl, snellerized, 660 bought here - litefoot's raffle saw #1
http://www.arboristsite.com/showthread.php?t=109333
Throughout the entire time, over a year, I had been looking for saws on ebay. And I only successfully bid on that one, although I did bid on quite a few others
My ebay criteria were Excellent reputation for selling saws, looked lightly used, seller could respond to picky questions, seller focused on saws and was not a pawnshop.
As another poster mentioned there are several great sellers on ebay. I would far rather buy from a seller with a great rep on ebay that only sold saws than a CL ad. But mostly it all boils down to money. Although I've only run about 6 tanks thru it I think my $515 was well spent. It saved me $500 off a new saw. Which was enough to almost pay for the second 660.
I'm happy to hear about the people that would never buy used on ebay, that means less competition. Somebody has to pay retail.