Other libraries have alternative selections for ebooks. For example, public libraries may be a good source for popular fiction. New York's public libraries have a large collection of ebooks and other downloadable material:
You may also find a great number of Ebooks in the public domain (any book written before 1922) freely available online. See below for several sites which offer free ebooks:
Search Google Books by keyword to find 1-3 uninterrupted pages in a book. Google Books is fully searchable, but it blocks continuous display of and disallows download in PDF format. Also see HathiTrust.