It's not an auction thing and it's a little different but your remark brings to my mind buying behaivor of books I see around here by the newbies. They buy tons of books I know are worth nothing. Or they pay high cash prices for books that have an online value of little more. I've asked some of them about this. Mostly it's a Fulfillment by Amazon thing. Those listings run higher price and sell faster than if you ship yourself. But you have to pay such highway robbery fees that the books you sell bring in around 50% of sale price. So the junk books have to be bringing in little profit. Maybe they figure that a lot of sales with tiny profit margins is the way to go. To each his own. But it seems to me to be an expensive way to do things.
For some it's not about the money but having something to do as kind of a side hobby. I fall into that category. A lot of things I buy in lots that I sort through I simply donate to various organizations, most books fall into that category. Some toys, puzzles, clothing and food products all get donated to schools, hospitals, food banks............
With regards to profit there is little difference between making $100 profit on the sale of 1 item and making the same $100 profit on the sale of 10 items other than your time and effort.
