Books are paid in cash, and the discount on teaching materials is generally higher. If it is not wholesale in large quantities, the discount is usually 7.5 or higher. If you can get all the students in a grade to buy the same textbook, you will earn more. There is no stipulation on how much to start the batch. At least you can't buy a book and approve it, because books don't make money. If you don't decide to buy, don't buy too much, because the textbooks are faster than the new ones, but some of them can be exchanged. You can take time to look at the details.