There is no such animal that I am aware of. There are price guides that give values based on condition, but I put very little value in their pricing.
You might find this site informative for top prices paid, but that will be dependent on which genre of music that interests you.
www.popsike.com
You might find this site informative for top prices paid, but that will be dependent on which genre of music that interests you.
www.popsike.com