Daedalus Books is an online bookstore that offers the residual, unsold new books, but you might want to give them a second chance. Their prices are really cheap, and you can get a discount of 10% if you sign up for their email list.
They are shipping worldwide, and the cost depends on the weight of the shipment. It might take 3-6 weeks for the shipment to arrive.
Better World Books is an online bookstore that offers free worldwide shipping. They offer new titles as well as used books and textbooks. They are affiliated with over 2300 college campuses and 3000 libraries. So far, they sold over 117 million books for $15 million, and put that into funding for literacy and education.
Paperback Swap is an online bookstore that is a little different because it lets you swap books with other users on the site. If you have a book to offer, you list it on your profile. For each book you send, you get one credit. You can use that credit to request a book from someone else, or to get a discount for the books this store offers.
For registering on this site, you get two credits, which means two books free of charge.
The Strand is an online bookstore that offers a wide variety of books and media; they have audiobooks, as well as physical copies. They offer new books, old books, collectibles, rare books, out-of-print books, and signes copies. You can even sell your old books, but they are picky about that, even if the book is in good condition.
It is possible to preorder a signed copy of a book, and they offer a discount for that.
Their shipping options are:
For the USA:
Econony: $3.99 for the first item, and $0.99 for each additional book; 4-14 business days
Ground: $5.99 for the first item, and $0.99 for each additional book; 2-6 business days
Second Day Express: $9.99 for the first item, and $3.99 for each additional book; 2-3 business days
Next Day Express: $19.99 for the first item, and $6.99 for each additional book; 1 business day
Standard: $9.99 for the first item, and $9.99 for each additional book; 7-30 business days
Priority: $29.99 for the first item, and $9.99 for each additional book; 3-7 business days
The rest of the world:
Standard: $17.99 for the first item, and $8.99 for each additional book; 7-30 business days
Priority: $39.99 for the first item, and $19.99 for each additional book; 3-7 business days
Booktopia is an online bookstore based in Australia, that offers:
Free shipping isn't available to everyone. Booktopia sends you an email when that option is available. During that time, you can pass the code to a third party (friend, family member, colleague, etc.). This is done because their shipping price is fixed, no matter how many things you order in one go. It's always $6.95.
This store offers their services only in Australia (including the rural areas) and New Zealand.
Audio Books Corner is an online audiobook store that is available worldwide. It also offers some free downloads. There is no monthly subscription. No extra softwares needed for playing their audiobooks.