7 Millionth on the Amazon sales list.
Cover art matters. Here's how.
Just for curiosity I picked one of the books on the awful covers list and went to the Amazon page to check out the reviews and the stats. The one I picked was published in 2008, had 2 reviews, and was #7,700,000 or something on the sales list. My first book, Bookman was published in 1990, was listed on Amazon in it's earliest small press effort and sold, like 5 copies through Amazon.
Bookman, out of print now for 20 years, is 6,000,000 books higher on the Amazon sales list than the book I checked!
The only explanation I can figure is that Bookman has remained on Amazon's sales list because used bookstores offer it. Most of those used copies (starting at 95 cents) are described as having been signed by the author. I sold about 1500 through Gordons and Ingram, of which I signed maybe a hundred. I gave away another couple hundred, most of which I signed. So, the signed ones are from friends and acquaintances I gave the book to over the years and they sold them at garage sales and because of the unique cover they have lived on as used books.
I paid an artist in Boulder, Colorado $200 to create a cover, which she did on poster paper with chalk. It seemed a simple picture at the time, but it made a compelling cover that a small steady trickle of people continue to buy today. It's a good story too.