Hi Lindsay,
Sometimes you can go through the publisher to purchase a digital version of the textbook. Unfortunately though, there is a cost associated with the digital version of the textbook and the student would be responsible for paying for the additional textbook in an audio version. Sometimes through you can find the audio version of the textbook at your local library. Keep in mind some of Penn Foster's textbooks we use are specific to Penn Foster programs and there maybe different versions of the textbook.