Bruce Reznick, University of Illinois at Urbana-Champaign Please send me additions and suggestions for this list. Note that the Web is fluid. Many publishers offer discounts on new books to AMS conference attendees.
Some people leave give-away books in the mailroom, or on tables outside offices.
Some people leave give-away piles of preprints and reprints in the mailroom, or on tables outside offices. Intelligencer, College Math. Look for elementary articles by advanced authors. Reviews of research papers. Mathematical Reviews, Zentralblatt, Ref.