One way to save money on books is to buy used books. It may take more time to search for what you are looking for but sometimes you can find unexpected treasures. Besides used book stores, there are some book sales coming up.
The Moorhead Library is having their Fall Used Book Sale Oct 1 and 2. The sale is Sat. 9-5 and after 2:00 all items are half price. On Sunday, the sale is 1-4 and books will be $5 per bag.
The West Fargo Friends of the Library is having a book sale Oct 14-16. Friday is for members only from 3:30-5:30. The book sale will be open to the public on Saturday from 10-4:30 and Sunday from 1-4:00.
The Fargo Library usually has a book sale also, but I could not find any information on it at this time. However, they do have books for sale throughout the year. At the Main branch downtown there is a room that is open at certain times. Their goal is to be open when the library is open, but it depends when they have volunteers. At the Carlson Branch, there are a couple of book shelves of books that for sale.
The Hope Lutheran Church at 3636 25th St S, Fargo is having a used book sale from Oct 9 through October 19.