A suggestion from philosopher David Velleman:

If people are worried about their local independent bookstores during the crisis — or even under normal conditions — they should consider buying their books from https://bookshop.org. This site enables independent bookstores to set up their own sites within the bookshop.org domain, with all fulfillment functions performed by a third party; and in addition to the returns the bookstores earn from their bookshop.org sites, they share in a pool of returns earned by sales from the central bookstore.org site. If your book its not yet available on bookstore.org, you can become an affiliate and list the book on your own sales site. You will then earn a share of the sales, but if you already link to your books on Amazon from your personal home page, you can switch those links to bookshop.org and format them in such a way that the earnings will go to your local independent bookstore instead, if they are also affiliates. (The format is https://bookshop.org/a/xxxx/yyyyyyyyyyyyy where xxxx is the bookshop.org affiliate number of the store and yyyyyyyyyyyyy is the ISBN-13 number of the book.)