As a reader, the one that is out of print and insanely priced used is Essential Thor Vol. 4. That thing must have had a short first print run and it never has been reprinted, yet volumes before it and after it got a second print. The goofy thing has been going for like $80+ used for probably 5 or 6 years. Don't know if many are being sold at it, but it's one of the few Essentials that I don't have.
And worse on it is the Thor that it's kind of been reprinted around in color too. I think with the last Thor Omnibus that came out finally got it out as the Masterworks was two copies, one of which was also out of print and crazy expensive.
― earlnash, Monday, 5 February 2018 22:31 (six years ago) link