I have a price point for books, but I also have a quality point for books too. I buy books that are sold to me DRM free, which means that the rights are MINE as to how, where and when to read the book.
I prefer that the book be substantially lower in price to the physical counterpart, because it still cannot outlast digital obsolescence like a physical book can.
Paper will always be readable except for physical damage. 20 years from now who knows, that drm'ed epub may not work on the new gadget I need to buy. But books I bought 30 years ago are still readable. Books are not something I should have to re-buy to fit the next gizmo that comes along. It's a book.