Is a offer of -20 percent on an OBO ad insulting?

Ditto Herman and Bundus.

If he is so uptight/disgruntled, let him rot in.........

I think it's the way you make the offer. How it's worded. Be polite, and maybe even acknowledge that while some might consider it a lowball offer, you don't mean to offend. Personally, I'm not insulted until about the 40% mark, but even then I'll thank them for their offer and politely say no. Bill and Ted are right--be excellent to one another.

Peace, Love, Dope
Dan

People here seem to have trouble with supply and demand setting the price. I love the guy who posted that "OBO" can mean more than the figure actually asked. "OBO" to my mind means the person has made a firm decision to sell on short notice and is willing to accept what is offered. If you can't stand the heat in the market place, get out of there. A polite "no" is all that is required when you think the offer is too low. Such audiophiles on top of being audio snobs in all likelihood are prima donnas. Let them keep their equipment. I suggest they become collectors. BTW I like the Canadians who want to sell in the US telling other Canadians wanting to know how much they want for it in Canadian funds that the item is sold and then who keep on advertising the item for two months on various sites. Jerks come in many shapes, sizes, nationalities etc but share one point in common.

20% off is not insulting, but depending on the circumstances it could be naive - which, of course, doesn't warrant a smack.

With that said, last week I put up for sale a very hot item NIB OBO at what would be market price for used ($700). Even given that, two people shot right back with "SOLD for $550. Give me address, I give you $!". This is annoying, regardless of the OBO advert notation because, even given that, these people were low-ballers. Even with that, I told them, thank you, no, and just reminded them of what they were bidding on - which is my way of getting rid of the people trying to swoop in on a price hoping for a newbie scared about spending too much (invariably guys trying to play used equipment dealer for a awhile...)

We do not know how this person asked for the price, or what the model was he was making a counter-offer on, but given his/her tone here, he hardly seems to be one of those guys.

There are lots of asses in the world just looking for a spot, always anonymous, where they can shout at the world. And so it goes...