Click on Kindle for PC for a free download of the software needed to read eBooks which use Amazon's proprietory format. Save the download and then Run.
Amazon's page of Free Book Collections offers access to many free classics and out-of-copyright, pre-1923 books as well as limited-time free promotional books available for Kindle.In addition to promoting the Kindle Store (currently 620,000 titles) the page lists online collections of older, out-of-copyright, pre-1923 books, which include nearly 2 million titles available to downloaded for free.
It should be noted that these large collections of older free books are typically created from scanned copies of physical books and can have variable quality.
Carl Cardey - Tech Tips