people amaze me

Did you list a specific price, or just asked for offers? Can't really blame someone for offering what it's worth to him / her, if you didn't give a starting point. If that's the case, at least they bothered to make an offer. As a buyer, I have two prices for most things. One is the price I'm willing to pay for something I want or need at the time I want or need it. The second is a price I would pay for something I have NO use for, but would not pass up if cheap enough. I imagine others use this logic as well. I think the person who NEEDS that block (and is within pickup distance) hasn't found your ad yet.

Now if you stated a specific price, and got a ridiculous counter offer, then that's offensive.