Everyone likes free stuff, and what's not to like? It's free! However, some people really like free stuff—like, really, really like free stuff—and they'll go to great lengths to ensure they get it, even fighting dirty and using tools such as guilt and anger to do so. This is one of the reasons why it's, unfortunately, best not even to bother offering free stuff online; you're bound to be inundated with people who have too much time on their hands and are combing buy/sell pages trying to be the…