Free versions of course texts with links to Kindle versions. You can also get these on Google Books, but please be aware that the free versions won't have all the materials.

Clemens, Samuel Pudd'nhead Wilson (Free version is the same text.)    
Frederic, Harold

The Damnation of Theron Ware

Kindle

Google Books

  Kindle version is the same but does not reproduce paragraph breaks correctly; both free versions lack footnotes and introduction.
Johnson, James Weldon

The Autobiography of an Ex-Coloured Man

Kindle

Google Books

1995 Free versions are the same as the print text.
Norris, Frank

McTeague

Kindle

Archive.org

1997 Free versions are missing the critical essays.
Melville, Herman

Moby-Dick

Archive.org (this contains the missing "Extracts)

Vol. 1

Vol. 2

  Kindle and Google Books versions of Moby-Dick are missing the entire first section ("Extracts") and the critical essays.
Hawthorne, Nathaniel

The Blithedale Romance

Kindle

Google Books

1983 Free versions are missing some phrases of the print text.
Wharton, Edith The House of Mirth 1984

Free versions are the same but are missing the introduction.