I often will bring up recently ended auctions and give the final prices (my offers are usually the exact same amount as the closed auction when I do this). Some people go "oh ok" and accept, or make a reasonable counter offer.
This is what I did when I made an offer on a Patagonia windbreaker that I wanted to buy for the Camino Frances I was planning to walk. The seller was asking more than what the item had sold for in the past on Ebay.
I made the seller an offer She countered with another offer. I then countered with another offer, pointing out the range that other Patagonia windbreakers had sold for. I also stated that I wanted to buy it for walking on the Camino Frances in Spain. She then agreed to sell it to me for my offer price. I think that stating why I wanted to buy it, as well as pointing out the range that the item had sold for in the past, convinced her to sell it to me for my offer price.