There should be a "Rant" category...

A couple of things: maybe the guy already had an offer and 10% was less than the offer so he wanted you to raise your price. Not everybody jacks up the price by 10 or 20%, so if he thought that his price was fair, then he had every right to ask full price. Possibly, if he just posted the piece and started to get activity, then I’d probably hold off for full price. Maybe wait until the end of the listing to ask for % off, you might have more negotiating room

A seller here posted his  price. I asked if he could do a percentage better. He calculated that my lower price was still beneficial vs waiting or not selling. I like to think we both won.

Why not counter with 7.5% or 5% off? It's called bartering. It's also how much you want the goods....

amg56"Why not counter with 7.5% or 5% off? It's called bartering."

Thats' is not even remotely what "bartering" is you obviously are in no position to advice, instruct or counsel those here about negotiating the terms of a sale or trade even though you want us to think that you are a shrewd, sophisticated or accomplished "operator".

Whether it's unreasonable or not depends on what did you want more -- the equipment or 100% of the asking price sitting in your checking account?