If your book is published on IngramSpark, IngramSpark’s Share & Sell purchase links allow you to create links that direct readers to a dedicated purchase page for your book. You can set special prices for your books for particular segments of your readers or for special events such as flash sales, gifting, and more. Ingram handles the transaction, printing, fulfillment and shipping -- and pays you directly.
You can learn more here: https://www.ingramspark.com/blog/get-your-books-into-readers-hands-with-share-sell-shareable-purchase-links.
After you generate a Share & Sell link, you can list that link in the Retailers tab on your Tertulia author website.