I know this is usually about ebooks, however there are times when you simply cannot find an ebook or, if you live overseas and don't use a VPN, the book you want may be unavailable. Anyway, assuming the mods don't mind (if you do, feel free to move this to wherever it should be),
Better World Books, which is my favorite dead tree online bookstore is running an end of year sale. They are offering 15% off 5 or more books or 25% off 10 or more books (all must be used and sold directly by them, not by "marketplace" listings).
Plus, and this is big news for the overseas crowd like me, they now offer free worldwide shipping on all books (one to to one million -- they all ship free).
Finally, for those who just want to feel good about where they buy their books, Better World Books collects books that would otherwise head for landfills all over the United States and then resells them for a few dollars. Profits go to support literacy programs in that country (I think they are a non-profit organization). Plus, they offer an optional "carbon offset" where they'll charge an extra 5 cents per book you buy and donate the money to plant trees, making the shipping of your books carbon neutral.
Again, it's dead tree books, not ebooks, but still, if you're going to buy paper books anyway, this is a good deal and a good deed as well.
Eric