College Student Buys & Sells Textbooks with Mark Sheffield | Bookdrop | Textbook Industry by Manga Sensei: Daily Japanese Learning published on 2019-10-29T10:00:09Z Mark started selling textbooks to make a little extra money and turned the hustle into a full-time business. Bookdrop is growing rapidly and is being used in 18 universities! 3:54 Bookdrop story. 9:37 How big the textbook industry is. 24:35 A general idea of profit per book sold. 26:55 the vision for Bookdrop and where it can go.