Sometimes, a seller will part with an item at a below-market price just for the satisfaction of seeing a newer diver enjoy the item that the seller got so much enjoyment out of. I have been on both ends of that. "Paying it forward." Buy quality gear and keep it in circulation!
I have been on both ends of that paradigm. I am happy to be on the giving end. Before moving back to the US, I parted with nearly all of my whitewater kayaking gear. a father and his young son walked away with over $2000 in gear including 2 boats in great condition for only 300 euros. It was liberating to be rid of it all and heartwarming to "pay it forward".
That being said, the prices people often ask for their used suits and reg sets both here and on facebook marketplace often seem a bit ridiculously high given the age of their stuff and how much it would cost new.
-Z