Or https://shopstr.store/

Don't know why plebian.market is offline right now.

Or if you want to sell your book in a totally self-sovereign way, without depending on any third party, just expand bitcoinmajlis.org with some shop features (using WooCommerce) and connect your BTCPay Server instance to that shop (there's a plugin for the integration of BTCPay Server). Sats would flow right from your own shop into your own wallet. Can't get more independent than that.