Best used book finder

The best online source for used books is BookFinder. Its bare bones design is unchanged from 1997 and feels like a Craigslist for books. It’s an aggregated meta-search engine that simultaneously looks for a book on Amazon, Ebay, Abe, Alibris, Bibio, and 100,000 indie booksellers. It will find all copies available and arrange them by price, and supply the link for purchase from the source. (In other countries and languages it is known as JustBooks.) It reliably yields the least expensive option for a used book. — KK