What to do with very low offer on an item for sale

@mitch2 They ARE Golden Reference.  In that era Golden Cross were blue (I have two pairs of those also).

http://www.element-acoustics.ca/archive/audio_visits/43-5.jpg 

Has an image of the Golden Reference - and a counterfeit.

They were purchased from the CableCompany in the late '90s.  Cardas later changed the color to Black.

I just say "no"

That one word can convey many different sentiments, for example it could mean:

- no, don't waste my time with your games

- no, go take a hike

- no, why do I even bother responding to guys like you

- no, WTF

- no, can you sense the annoyance

You get the idea

That's pretty much the same sentiment.

when the offer is super low, I usually play along and respond with an even lower counter. 

Why get worked up over this?  There are plenty of unreasonable sellers also, which are attempting to get close to new prices or well above fair market value.  Do you email each seller also just to prove a point?  It's your choice to engage...or not.