Off and on I have this sort of thing happen on auctions of mine. They will watch and wait until after it is over, hoping no one will bid, then contact me to try offer me a low ball price hoping that I will be desperate enough to accept it instead of simply re-listing again or selling outside of ebay, like on CL or something. They send messages like 2 mins after the auction has ended flat out telling me they did not agree with my low bid price, but asking if I would accept so and so amount. Usually they are resellers. The last guy who did this was a dvd reseller going by the name foxhound852. I told him instead of relisting my stuff I was selling it to a friend, that if he wanted it he should have bid, "you snooze, you lose".
The guy wanted to persistently message me after this anyway so I ended up reporting him to ebay for pestering me about trying to have a transaction outside of ebay. I had my fun with him too and added him to my blocked bidder list. It also happens that the guy had feedback from a recent seller that he tried to extort money off of on an already awesome 67 DVD lot he won for 79 bucks shipped. These people usually try to get things as low as possible for their resell business. They will make up complaints to try to get money back off you or free shit all the time that they will say arrived damaged and crap, but suddenly have listed for sale in the exact condition you sold it in.