If you have a chance, go to the library

and borrow a copy of Daniel Ariely's
Predictably Irrational.
In it, he offers numerous examples of how attaching any price whatsoever -- even 99¢ -- radically alters behavior. In short: "Free" generally gets treated like a social service or good. Assigning any dollar amount instantly changes it to an economic relationship.
Libraries also do more than just hand out books, of course. They have a separate value as a social space for a community.
So despite the fact that $1 ebooks abound, chances are slim that this would truly replace the function of libraries.