While we are discussing free Kindle books, Jane Austen's birthday was yesterday (Happy Birthday, Jane! I'm so happy you were born!) and to celebrate, many Kindle editions of her book were free and still are today. Many other modern interpretations of her books are free, too. Here's a list. Please confirm price before buying because these are subject to change at a moment's notice.
Jane's own titles, which would be free from many sources but the illustrated versions are nice to have and not as commonly available:
And the other modern titles are, read at your own risk, but they are free and usually not: