So, here's the hostility I'm talking about. I mean, if someone offers $300 for a nice P226, I get it, that's ridiculous. But, if you have something priced at NIB levels and you're offered a more reasonable used price, how can you be mad at that? Or even if you're offered a "lowball" price, you can just say no and end the conversation. Or if you are a little more savvy, and not so cranky (you're too young to be so cranky, Austin) you could negotiate a sale that is palatable to both parties. A good negotiation is one that leaves both parties satisfied. By getting all pissed off at the lowball offer (even the $300 guy) you may be losing a sale that, had you taken the time to talk to the person, would have ended up as a win-win.
It always amazes me when people dealing in used items are unwilling or hostile to negotiating. It really doesn't make any sense, unless you absolutely just don't care if you sell it or not.
I get this too... but a lot of times, the LOW BALL'R gets offended when you say no and tries to convince you he/she is justified in the offer!