Organizations intermediate in manufacturing and distribution process such as wholesalers and retailers.
Retailers, and vendors that distribute our boxed products
Companies that buy books with the intent to resell them. These are either wholesalers (like Ingram) who sell to retailers, or retailers (bookstores) that sell to the public.
Telecommunications companies that sign up with long-distance carriers for volume discount plans and then pass those savings on to small companies; also, furniture brokers who purchase existing lots of furniture and sell it as is without any warranty.