Even if you prefer a print book, there are times when an ebook may be just the very thing. It is dark, you have just finished the last print book you have with you, you want to check out a new author before committing to purchasing the book….
Check out this summary from the Consumer’s Checkbook. https://www.checkbook.org/washington-area/eread-for-free/
Sources can include your local library, Project Gutenberg, and freebies from booksellers.