When I had my shop open, I sold far more items to dealers than I did to the general public.
I made my profit ….. and I assume they did also ….. because many came back again n’ again.
A lesson I had to learn though, …. if someone brought an item in to sell to me, …. I would never quote them a price I would pay for it.
Because iffen I did, more often than not, they would take that item to another dealer and tell them …… “Sam offered me $$$ for it, ….. how much will you pay for it?”
HA, they were operating a “private” auction ….. with the dealers being the “bidders”.