Used bookstores do not only buy remainders and bargain to fill the niches and gaps in their inventory, which they do aggressively, but also to seed their community of customers with future used inventory. Books which they sell to a customer as a remainder this year might come back as a much more valuable used book in 5 years, or 15, or 30.
Some used bookstores treat remainders and bargain as sidelines, however not so much as do trade bookstores. For used bookstores, if they carry them at all, new books are sidelines, just without the profit margins. For most used bookstores that buy bargain, it is an integral and significant part of their bottom line.
I have mentioned here in past posts the disconnect between the media driven public perception of the decline in bookstores and the interactions I have with almost every bookstore I deal with telling me their sales are either up or so extremely up that they don't want to say by how much for fear of luring competition to town. Used bookstores are typically ahead of this disconnect, having arrived at that level of health earlier and surpassed it by a few factors. Buyers at used bookstores are ahead of the rest of us when it comes to knowing what will sell, what sold, sells, or will lie gathering dust on the bottom shelves.
Yet used bookstores are not impervious to the economics that have tightened the margins of booksellers everywhere. They too have had to go back to school for marketing, branding themselves, and customer service and relations. Some have closed or reduced staff, reduced their space or moved to less desirable bookselling neighborhoods. But most have weathered the storm in very good to fine condition.
There are used bookstores that get most or all of their stock from donations. They either opened for business with donations as the central feature of their business plan, or they hit hard times a few years ago and decided that this would be the only way to stay alive and have since either survived or thrived. Most of them also sell on the internet and there are some that only sell on the internet, so much so that they are among the largest online booksellers. It might sound simple to the uninitiated, but it is not an easy way to do business. Lots more heavy lifting and the time and space spent sifting and winnowing takes some serious planning. Community relations play a big part.
Donations have always been a piece of the used book business. Paperback exchanges have a donation component in their business. All used bookstores, at one time or another, have opened in the morning to discover some harried anonymous book hoarder's vast discarded library pyramided against their front door. Sometimes people need to shed the books and can't bear to throw them in the trash, but also can't bear to stand there and hear the buyer's offers. They might take a few dollars for part of their library and walk away from the rest.
These used bookstores can come back strong, and some thrive and grow and begin buying again. If the business plan must be to operate as donation-only to survive, then it's a good thing.
But most of the used bookstores I do business with have been buying from me since the beginning of my wholesale career, as they have from everybody in my line of work. They tend to have very knowledgeable buyers, who look carefully at every title. They are completely comfortable buying books that cannot be returned to publishers because this is the only way of doing business they've ever known.
An acquisition editor I know goes frequently to a large used bookstore, watching how people choose what they buy, listening to what they ask for. He once said that if his job no longer required or allowed him to do this, he would have to resign and find one that did.
Used books, like remainders and bargain books, are counterpoints to the homogenization of retail in general. New books are the wonderful, glossy skin of the book world, a few months old, all about now. Used books go centuries deep. There is something about a used bookstore that draws us in: the last surviving ancient magical cave of wonder.