I've been using the Sony e-reader for about 3 years now and have never purchased a book.
I borrow ebooks from my library and transfer them to my reader.
All it takes is a library card.
I just picked up the new Sony e-reader for the wife and this one has built in wi-fi and connects directly to my (or yours) library.
Wife can check out her books directly on the sony
About $120 from B&H