Standard Ebooks is one of the best ways to find public domain literature. Looks beautiful, entirely free: <a href="https://standardebooks.org/ebooks" rel="nofollow">https://standardebooks.org/ebooks</a>
Here to echo that praise. One of my hobbies, starting many years ago, is reading about 15th to 17th century England. This used to be a bit expensive and often severely limited to secondary sources that could be had in local bookshops and libraries (which is even more limiting for me, as I live in Japan). But the Internet Archive has dramatically changed that, with thousands and thousands of scans of primary texts, from broadsides to bibles to bestiaries to ballads. I imagine anyone interested in any period or phenomenon that pre-dates the 1923 public domain hard cutoff shares that excitement.<p>The Internet Archive is free, but they accept donations – I would say it's one of the best ways to spend money if you're a user or fan of the preservation of historical texts and files.