According to the students' ability in the university campus, if the monthly living expenses are around 600-800, and if the purchase price is around 1, you can sell a book in 2.5 yuan, and you can read it in turn after buying it. If you don't read it yourself, it's invalid. You can also consider the price of color map and achromatic map. It is necessary to distinguish between girls who mainly watch some love stories and romance novels and boys who mainly watch sports and some sports shoes. Big pictures will attract boys' attention. The basic price has doubled or so. I am a student, so I think this price is acceptable to me. I don't know how to answer this question. I also wish you value for money and success in your studies.