There are some Python programming books available online, with full text, from other sources as well. Here are a few:
LibreTexts - Computer Sciencelessens the burden of student costs by providing open access texts kept up-to-date by students, faculty, and outside experts. Started by UC Davis.
SpringerLink - Computer Science"offers the latest in cutting-edge research to prepare students and seasoned researchers alike for an impactful career in this diverse and fast-moving field."
Open Textbook Libraryis a comprehensive resource offered by the University of Minnesota for openly licensed academic textbooks. All textbooks are free, and the majority are peer reviewed.