Many independent publishers sell titles from their own website, as do many large ones (i.e.: Simon And Schuster, HarperCollins). You should definitely check those out. S&S in particular runs 30% off deals on nearly all their titles, usually making it cheaper to buy from them than another etailer. We usually will uncover a coupon or two for them, which we post on our Steals And Deals page (
http://knowbetter.com/DesktopDefault.aspx?tabid=35) which will get you an even bigger discount. I find I buy quite a bit from them.
To title hunt by subject, I recommend taking a look through our Ebook Directory (
http://knowbetter.com/DesktopDefault.aspx?tabid=25). It represents 11,000+ titles from 150+ publishers. We don't actually sell the titles, but each listing has a link to where you can get it.
Best,
Jay Hartman
Content Editor
KnowBetter.com: For Everything Ebook
http://www.knowbetter.com