My favorite book is a little known one called “Black Holes and Timewarps: Einstein’s Outrageous Legacy” and I reference it so much that I would really like a copy that’s fully mine and searchable, but I also care about the author receiving compensation for the purchase. Where do you get your PDF copies from?
I’d suggest contacting the publisher and see if they can work out a special deal for you.
You probably will need to be a bit persistent as the first person who you reach will probably be following a script to reject you.