"An Utterly Biased, Random, and Partial List of Books (in No Particular Order) I Think You Should Read Sometime, And Only Including Books that I Have Actually Read .
If books are out of copyright and in the public domain, then they are easily found on the internet (although they often need re-formatting). www.manybooks.net is a good source, as you can download texts in a variety of formats.
Other good places to try:
If you have a Kindle, or the Kindle app on your PC or iPad, you can search on Amazon for free books (yes, they do exist).
If there is no hyperlink for a text below, then the book is either still copyright, or I have not been able to find an online version.
The “Anything By ...” List