I've got a couple of very interesting articles about independent bookstores and book sales:
Book Sales News in U.S. for 2018 Announced
One more announcement:
Books, Inc. is having its semi-annual warehouse sale on Saturday, July 20, at 150 Vermont Street, San Francisco. It starts at 9:00 and goes all day. And they not only have thousands of books on sale at a 30%-80% discount. They also sell toys, greeting cards, gifts, and even furniture! Don't miss it.