Many libraries have tons of Ebooks to lend out. It's more convenient than going to the library (since it's all online), but otherwise the same deal. Check out, read it, and return it.
(1 crappy thing is that the library can only lend each copy a set number of times before it is 'destroyed', but I guess that's intended to match how physical books would fall apart. It's not ideal, but still - SUPPORT YOUR LOCAL LIBRARY!!)