I don't know why this story has stuck with me for so long.
A favorite series was the "Riverworld" set by Philip Jose Farmer.
From the first SF book I ever picked up, PJF was always consistently good, and became one of my favorite authors.
I liked some of David Brin’s books. “Startide Rising”, its prequel “Sundiver”, and the Uplift series really kept me waiting for more. “The Practice Effect” didn’t really catch on to me. IIRC it was reverse entropy. Something had to be used often to become perfect. A crude tool would become better if used over and over. Poor people could earn a living by “practicing” items (including clothes) for wealthy clients.
I think that’s Oblahblah’s plan for the mints. If he runs them long enough they’ll make the perfect dollar. In his eyes that means one worth nothing.