Offer / counter-offer? Audiogon rules

Why ask opinions when you can simply email support?  They are incredibly timely in their response and will give you a definitive answer. 

I always list with the buy now only. If someone wants to make an offer they will email me and if I accept I will change the price and the deal is done. I’ve been selling here since 2004 and I have never had a problem doing it that way!

Rather than make an official counteroffer, I sometimes will tell the potential buyer what I'd accept and leave it up to them to submit another offer.  For example, let's say I'm selling a piece for $1000, and someone offers $850.  I will decline the offer but send a note thanking them and saying that I would accept $925 but won't go lower.  Then it's up to them to decide whether that price is acceptable.  If they offer anything lower, I just decline with a "no thanks."