I have brought, sold , and traded vintage home stereo piece's from the mid 70's to early 80's (Wattage Wars) for many many years. What I found is : the correct price is what both parties are happy with
Value for something that has no set price (Org. Cost, Cond. Service, History, etc) like these stereo's or our Cobras, again come down to both parties agreeing what each is willing to give or take. I've also found when you're dealing with someone that is selling something that has sentimental value for Goodness sake treat them with RESPECT! Please do not pick apart (While their standing there) a (Car, Stereo, etc) that the loved one had chariest forever, trust me I know this to be a fact, and you can still get a good deal. Common sense goes a long way on these deal's. Put your self in their shoes. I hope this help's in some small way. Cheers Tom.