Okay, my confusion is this -
I assume a promo copy is circulated to radio stations, etc before the actual release of the record. I’m talking about records from the 50s to 80s, btw, not sure if it matters. And therefore, I assume less promo copies are made than the official release records. I would then think that because less promo copies exist, they are worth more than the official release version. Comparing the versions should eliminate the artist as a variable because it is the same artist and album for both, and if promo copies are always made in smaller volume than official release, that would logically eliminate that variable as well. On the other hand, I seem to have heard somewhere that promo copies are worth less. Any or all of the assumptions I’m making here could be wrong; I’m really not sure.
I don’t really care what promo copies are worth relative to each other, more what they are worth relative to the regular version of the same album that people would have been able to buy at a music store.
I have a bunch of old records, some of which are promos, and I am trying to price them. There’s not much to go on besides what other people are selling the same, non-promo album for.