All books from Charles Harness are on discount, both in USA and in Europe; the starting price was not so high (usually 3.99, in either Euros or in $) and is now 1.99 or .99. Both on Kobo and Amazon.
Best ones (my taste) are The Rose
https://www.kobo.com/it/en/ebook/the-rose-16
https://www.amazon.com/Rose-Charles-...les+L.+Harness
and The Ring of Ritornel
https://www.kobo.com/it/en/ebook/the-ring-of-ritornel
https://www.amazon.com/Ring-Ritornel...les+L.+Harness
I will not list the others, as it is easy, just search for the author name in both Kobo and Amazon.
Harnes is not well known, and has published few books, starting from the 50s of last century, till 2001 (according to Wikipedia) and it is well worth reading.
I read it when I was younger, and I sort of remember some review comparing the Ring of Ritornel to a VanVogt epic.
As an author, he was quite complex, stylistically. Worth trying.