I have taken part in local bonsai auctions in the past, and even auctioneered once before. This year I was asked to be auctioneer at Bay Island Bonsai's Tenth Anniversary Exhibit. I remarked how much I would love to produce an exhibit just from the auction material available at that show. We had 93 lots, everything from collected stock to finished trees, as well as a few other items as well. Not everything sold, of course, since there were reserves on most items.
BIB does this a little differently from some clubs: donors receive 80% of the proceeds and the club receives 20%. Nursery material in a nursery can had to be something very special or it went into the sale area instead of the auction. It was a wild ride, and took 2 hours 20 minutes to go through all 93 lots. We sold over $20,000 worth of material.
As I mentioned, some things did not sell due to the reserves. However, the exposed root Japanese black pine you see below had a reserve of $500 and sold for almost twice that. It has been grown from seed for 15 years and is ready for a first styling. It was about 10-12 inches tall overall.