The costliest part of this audio journey for me is my inability to sell gear.
I sure I'm not the only one afflicted with this disease. The upside is that I find Easter Eggs when I'm hunting for something in the house that is unrelated. Recently found three Hafler amps in a closet and a GAS amp (remember those?) in the attic.
The only piece I ever sold was a Teac A-3340S 4 channel RTR, because I had two of them!
Upon leaving college I "sold" a pair of B&O speakers to my room mate. They were very good at the time mid-70s.........costly yes, because I never got paid for them.