These are the books I wrote. If you want to download them, you can buy them and pay what you think is worth for them, or just read them online without having to worry about any of that.
This book teaches the basics of Python. Data structures, basic operations, some of the main libraries to do regular day-to-day work. Plus, you get to learn how to work with dates, dealing with files and handling exceptions. I try to provide lots of examples and to write in a language as clear as possible.