I buy more than I sell... Hopefully that will change, so I'm sure I'll have some future storeies.
And I've had a few seller sellers that are flakes. I've had a few sellers agree to meet, then sell the items out from under me. There's one bike on Craigslist now... not a peep out of the seller (e-mail only). It could have sold quickly, but the ad has not been up for over a day.
As far as dickering... If you don't want to dicker, the put "Firm Price" and stick to it.
I will give an offer on some things (the E-Bay "best offer". And, I hate it when the seller hits me back with a $1 off "deal"). But, usually, if I think it is a good price, I'll just pay the full price. If it is a really good price, I'll round UP from $75 to 4x$20 ($80). And the seller is happy, and I'm happy.