Learn Python the Hard Way – “the way people used to learn things”; very incremental and great at teaching you to debug IF you follow directions. Older versions can be found for free online and with the author’s permission; the latest version is $30 and includes access to videos.

Scientific Computing with Python (FreeCodeCamp) – based on University of Michigan’s Python for Everybody, with a certification available at the end of the course.

Python for Everybody – free book (and on Coursera if video learning is your thing)