I've been to a library book sale. Other Book Sales I've attended were held on a certain date, and books sometimes cost as much as $2.00 each.
This book sale is ongoing. As books are removed from circulation and donated books are deemed unsuitable for the collection of this particular library, they are shelved in a corner of a workroom. If you want to see what is there, you must sign in with your name, the date and where you are headed: BOOK SALE. Then you are allowed to pass through the door with the ominous sign, No Patrons Beyond this Door.
They're pretty much shelved by fiction, nonfiction, Large Print and media items. Some of the fiction looks brand new. A John Grisham book that I bought there in paperback two weeks ago has been replaced by a hardback with dust jacket intact.
Among the treasures I found today was 'The Fragrant Year' by Wilson & Bell, 1967. So it's 40 years old! Flowers smell essentially the same today as then, except that the fragrance has been hybridized out of a few. The oldies that I grow still smell good, except for my Philadelphus inodoratus, which has no fragrance.
Another treasure is 'A Gift of Joy' by Helen Hayes, 1965. Maybe I'm the only patron who remembers Helen Hayes. In the photos in the center of the book are included a photo of Helen 'among the perennials' and 'under my white magnolia tree.'
I also bought two other paper backs, not novels -- trade paperbacks, another hardback, and 14 audio books. They're phasing out audio tapes for CD/DVDs. My total was $1.45.