During this era, the early 1930's, in the South, the schools were small rural schools that didn't have much money. The people didn't have much money either and couldn't afford to go out and just buy books when they wished.
The schools were Black children attended were not really funded very well at all. Most of their textbooks and reading materials were passed down from the "white schools." At one point in the story Cassie refuses to take a "new" book because it had been handed down from another school. These books were used, old, and not in very good condition. Whenever the students got new materials it was a treat. Even when some of the books were "hand-me-downs" it meant a lot for the students to have books.