Give us more details re condition of gun, barrel length, box, etc.
Yes, I should have given more details. I'm looking for a 4" in good enough condition that I can shoot it (mostly at the range but some carrying around my property) without ever having to worry about it giving problems. Obviously, any 66-0 is about 35 years old and there's a wide range in ones well-used and ones not well-used. So I would expect a wide range in price/value.
I've seen some highly polished guns at a higher cost but I'm not so interested in the exterior look so long as the gun locks up tight and has good, crisp rifling. It's hard to assess that from a distance without paying for a gun promised to be "little used".
Theres one on GunBroker now in a display box (which I do not want) that looks very clean but is $755. This gun has been offered for awhile and started at $820...
PS. I recently asked my local gun dealer (The Gun Doctor, Longview, TX). He had nothing and had not had a 66 in a long time. He looked it up in his computer network of other dealers and could not find one anywhere in whatever range he was using.