The bill aims to reduce the cost textbooks by expanding the use and awareness of open educational resources at college and university campuses. It would provide permanent authorization for an open textbook grant program.
Background information and description from SPARC (Scholarly Publishing and Academic Resources Coalition)

Text of the Affordable College Textbook Act: S. 1864 -- 115th Congress (2017-2018)

Text of the Affordable College Textbook Act: H.R. 3840 -- 115th Congress (2017-2018)

SF 2415 / HF 2544
This law asks instructors to identify, review, and approve OER for use in the their courses, and colleges to offer the opportunity to earn a zero-cost degree.

The Open Textbooks Pilot program supports projects at eligible institutions of higher education that create new open textbooks and expand the use of open textbooks in courses that are part of a degree-granting program, particularly those with high enrollments. This pilot program emphasizes the development of projects that demonstrate the greatest potential to achieve the highest level of savings for students through sustainable, expanded use of open textbooks in high-enrollment courses or in programs that prepare individuals for in-demand fields.

The Open, Public, Electronic and Necessary (OPEN) Government Data Act provides a sweeping, government-wide mandate for federal agencies to publish all their information as open data – using standardized, non-proprietary formats.

A nationwide coalition of student government leaders who are working to bring open textbooks to college campuses. Their goal is to reshape the textbook market by fostering a marketplace where open textbooks can compete with, and eventually replace, traditional textbooks.

SPARC is a global coalition committed to making Open the default for research and education. SPARC empowers people to solve big problems and make new discoveries through the adoption of policies and practices advance Open Access, Open Data, and Open Education.

The federation of Public Interest Research Groups. A consumer group that stands up to powerful interests whenever they threaten our health and safety, our financial security, or our right to fully participate in our democratic society.
They have worked with SPARC to advocate for the Affordable College Textbook Act.

They work with professional staff at colleges and universities to make sure their peers have the skills, opportunities and training they need to create a better, more sustainable future everyone. Their chapters on 35 campuses provide the training, professional support and resources students need to tackle issues such as: the affordability of college textbooks, climate change, protection of public health, revitalizing our democracy, feeding the hungry, etc.