How to save $85.50 on books

At the library book sale today, I purchased 89 dollars worth of books for the grand total of 3 dollars and fifty cents. The titles I got are:

The Consolation of Philosophy (pb) by Boethius for $.50.

The Lucifer Principle: A Scientific Expedition into the Forces of History (pb) by Howard Bloom for $.50.

Dune (pb) by Frank Herbert for $.50.

The Age of American Unreason (hc) by Susan Jacoby for $1.00.

Broken Government: How Republican Rule Destroyed the Legislative, Executive, and Judicial Branches (hc) by John Dean for $1.00.

Liking to consider myself an amateur forensic book detective, I like to see if I can reconstruct the life of the books I get preceding my purchase of them. Judging by the wear and tear on Dune, The Lucifer Principle, and The Consolation of Philosophy, these books enjoyed a relatively normal life of library books that were checked out and read semi-regular. Broken Government, however, is mint. I would guess with about 98% certainty it has never been checked out, much less read.

The Age of American Unreason was a book sale donation, meaning it is from someone's personal collection and was not a library book. The actual book itself would seem to indicate that it has never been read, despite the book's jacket having slight wear: the front is near mint, but the back has sustained some moisture damage and has a ring from someone sitting a drink down on it. I would conclude that someone was given the book as a gift, put it down on their coffee table and never read it, or never did more than flipping through it.