I got several great deals on double shotguns on Gunrunner before they were so well known. There was little competition in bidding, so a lot of guns tended to go cheap. Not so much anymore, and the new website is painfully slow to navigate compared to the old one.
Auctions are always unpredictable. Local auctioneers can be great places to sell if the auction is scheduled on a nice sunny day when a good crowd can attend, and if the sale is widely advertised. I went to a local estate auction last year that had about 25-30 guns to sell. The auctioneer sold a gun about every 10 lots rather than selling them all together. He knew this would keep much of the crowd from leaving after the guns were sold. Half a dozen common Winchester Model 88 lever actions sold for at least 50% over full blown retail. Most surprising was a Winchester 1895 lever gun in .30-06 which went for an astounding $1750.00. This gun was heavily and poorly buffed and refinished. All it was good for was a shooter, or for internal parts. I left shaking my head, and thinking that I should buy junk guns to resell with this particular auctioneer.
