What I think I deserve for free is the ability to decide whether a book is worth the price or not. This is simple in a bookstore, but when I’m online the default seems to be that I have to shell out to even take a look.
It’s not roughly equivalent. I often look at the free previews on Amazon and Google Books to check print citations or read a few pages from a chapter of interest, but usually the pages I want to read are unavailable. An online equivalent to bookstores is not possible because there’s no way to glare at a customer for treating the store as a library.