You can download e-books for free from major e-book stores (such as Amazon's iPhone, Apple's iBooks, Google Play Books, etc.). These stores usually provide a wealth of free e-book resources. In addition, you can also find free e-books in the digital resource banks of some public libraries such as the National Library of China and the Shanghai Library. Other websites also provided free online listening services such as Netease Cloud Music and Himalayan PM. I hope these suggestions will help you find a free e-book to listen to.