Am I crazy? I found this "chest" or at least just the money marker for a chest and I had enough money. I could not purchase the "chest" or whatever the interactable was, no matter where I was, I ran all over the area spamming e.
#Unbuyable invisible chest
clever bane
clear lake
Had this happen before in the same area, the chest spawns underground, iirc it can be bought but requires some precise angling.