English Comp Textbooks.

In another pass through Amazon looking for cheap textbooks, here's what I have found for English Composition.

A Writer's Repertoire - used starting at .08 cents.

The Bedford Guide for College Writers - used starting at $2.35.

English Composition and Grammar: Complete Course - used starting at $7.16.

College English and Communication - used starting at a penny.

The Composition of Everyday Life: A Guide to Writing - used starting at .08 cents.

Inexpensive world history/western civilizations books.

Just like with the science books below, I did an Amazon hunt for history books, for anyone who prefers to have a printed textbook to read. As always, these links are merely FYI. They aren't affiliate links and you don't have to buy anything here.

World History to 1500, 2006 edition, used from $1.20.
World History, Volume II: Since 1500, 2006 edition, used from $3.00.

The World's History, Volume 1 (to 1500), 2005 edition, used from $3.00.
The World's History, Volume 2 (since 1100), 2005 edition, used from $0.36.
The World's History: Combined, 2000 edition, used from $11.99. This is a combined volume of the previous two books. It's actually, (even with shipping), still cheaper to buy the separate, newer books, but I included it because there is, as of right now, one seller selling it new for $18, if you prefer new books.

The Heritage of World Civilizations, Volume 1, 2008 edition, used from $2.00. (There's a 2002 edition HERE starting at $0.08.)
The Heritage of World Civilizations, Volume 2, 2008 edition, used starting at $9.56. (The 2002 edition HERE starts at $0.51.)

Western Civilizations, Volume 1 2002 edition, used from $0.34
Western Civilizations, Volume 2, 2005 edition, used from one penny. (No, really.)
Western Civilizations, Brief Edition (One-Volume Edition), 2005 edition, used from $1.99. (This is the condensed version of both previous volumes, combined.)
Western Civilizations, Single Volume Edition, 2002 edition, used from $1.78. (This is the full version of the two volumes, combined.)

Western Civilization: Brief Discovery Edition, 2005 edition, used from $0.51. This is a different textbook than the other Western Civ books above. (And keep in mind, this "brief" book is over 700 pages long.)

The Western Heritage, 2000 edition, used from $0.98.

Inexpensive science textbooks.

In keeping with the earlier post I made about finding inexpensive textbooks, I've done a little digging around on Amazon and found the following. Even with the $3.99 in shipping costs per book, none of these books would cost you more than $17, if you purchased the least expensive one for sale, and most of them would come in under $10. Although CK-12 provides free science textbooks, if you don't want to be reading everything on your computer or mobile reader (Nook, Kindle, etc.), buying a used textbook like any of these is cheaper than printing out the free books, when factoring in ink and paper. (Reminder: These are NOT affiliate links - just here FYI):

Environmental Science: Principles, Connections, & Solutions - 2007 edition, used starting at $1.79.

Environmental Science: A Global Concern - 2007 edition, used starting at $13.00.

Earth: An Introduction to Physical Geology - 2002 edition, used starting at $0.35.

The Good Earth: Introduction to Earth Science - 2007 edition, used starting at $1.99.

Biology - 2007 edition, used starting at $4.93. (According to the description, this book has 1259 pages and weighs over 7 pounds! Sheesh.)

Biology: Concepts & Investigations - 2008 edition, used starting at $4.49.

Introductory Chemistry: A Foundation - 2003 edition, used starting at $10.86.

Chemistry: An Introduction to General, Organic, and Biological Chemistry - 2005 edition, used starting at $4.00.

Astronomy: A Beginner's Guide to the Universe - 2006 edition, used from $3.50.

Astronomy: The Evolving Universe - 2002 edition, used starting at $7.97.

Physics - 2004 edition, used from $6.41.

Physics: Principles and Problems - 2004 edition, used starting at $13.00.