For a free option, don't forget about your public library.
If you purchase a Kindle eBook (AZW3) but need an EPUB, tools like (a free, open-source eBook management software) can be used to convert the file format for personal use. Please note, this should only be done with files you have legally purchased and never for distribution. First Flight- Final Fall by C.W. Farnsworth EPUB PDF
At the same time, Farnsworth is not afraid to take creative liberties to enhance the story. The result is a novel that feels both historically grounded and engagingly fictionalized. For a free option, don't forget about your public library