I recently received a simple query on one of my parked generic domains. "Are you interested in selling this domain name? If so can you please contact me" There wasn't enough information to know why this person might me interested in the domain in question, so I knew I'd be negotiating blind.
Unless there's some reason why the person really wants that specific domain name, queries as simple this go cold when I quote a realistic starting price, so I shot back a quick one-liner "Yes, I would be prepared to sell it, I'd want NZ$ 500 though." and didn't think any more about it.
Two days later a reply "Would you except[sic] $300.00."
Normally I'd haggle about the price & probably settle for around $400, but I just felt like I'd like a little more.
My reply:
This was replied to 20 minutes later with an agreement to pay my asking price and the money's now in my bank.
5 minutes researching a value for the domain and writing two short paragraphs increased the price $100 over what I would normally have accepted.
Lesson learned: you don't have to drop the price if you can convince the purchaser that it's legitimate.
Domain buying seems like the Wild West sometimes with all the different methods of buying, communicating, and having so many factors going into the valuation of a domain.
Tip: Negotiate not haggle 
