You can get two Lisp-related books for free on Leanpub:

There’s also a book on the Hy Programming language, a Lisp-like syntax alternative for Python.
The book A Lisp Programmer Living in Python-Land: The Hy Programming Language is not free, but available for a minimum price of $ 5.00.
It contains some practical projects for Hy, for example, web-scraping with the library Beautiful Soup, or Deep Learning with Keras and Tensorflow.