The amount a country spends on learning materials is a good indicator of its commitment to providing a quality education for all. While there are various types of teaching and learning materials, this paper will focus on textbooks, which are the most commonly used type. Textbooks are especially relevant to improving learning outcomes in low income countries with large class sizes, a high proportion of unqualified teachers and a shortage of instructional time. Next to an engaged and prepared teacher, well-designed textbooks in sufficient quantities are the most effective way to improve instruction and learning. Yet as this paper shows, in many countries students at all levels either lack books altogether or are required to share them extensively with others. Without textbooks, children can spend many of their school hours copying content from the blackboard, which severely reduces time for engaged learning. The cost of textbooks is a key barrier that prevents children from having access to the learning materials they need. This paper investigates the cost of textbooks and the miniscule budget currently allocated to textbooks by many developing countries. It considers how the innovative finance model used by Gavi, the Vaccine Alliance, could encourage private sector investment in the textbook sector. New GEM Report analysis shows how following this model could take US$3 off the price of each textbook, saving almost a billion dollars from the cost of textbooks in sub-Saharan Africa alone, and tripling the number of textbooks available to children around the world.