In the Internet age, I believe you will often see some free public welfare books in the circle of friends or some groups. It said that in order to keep children away from electronic devices and return to paper reading, children in poor areas can advertise and sell books under the banner of books. When you join the group, you will be asked to send a circle of friends, then choose books, pay postage and fill in the address.

When you have done everything, search the price of books online. Originally advertised the price of one or two hundred, and sold it online for one or twenty or twenty or thirty yuan.