I still buy cd’s and vinyl. I also sell some stuff trough Discogs. It really depends what you sell, what you get. I sold cd’s for 30 euros, mostly the more rare Japanese editions. But really, most cd’s are worth somewhere between the 5 and 10 euros, especially the more common stuff from Blue Note, Verve, OJC etc. The really more older jazz from the ‘30’s and so really not seem to be in demand.
In most cases, the Median Discogs price is quite a good guideline. The marketplaces really are not.