After you download it, go to any site where you can download the PDF or EPUB format of the books you want to read. Then, upload them from the "Add books" tab, convert them to MOBI format, and connect your Kindle to send them to your device.
You'll never have to spend money on Kindle books again.
All you need is the app Calibre on your laptop or PC.
Here's the link in case https://main.calibre-ebook.com/download.
After you download it, go to any site where you can download the PDF or EPUB format of the books you want to read.
Then, upload them from the "Add books" tab, convert them to MOBI format, and connect your Kindle to send them to your device.
You'll never have to spend money on Kindle books again.