Lisp is awesome, but I wish more places used regional pricing for online purchases. It's kinda crazy paying 40 dollars for an ebook since it's almost 1/5 of our minimum monthly wage (Brazil)
2021 was the 2nd year in a row that there was sales on Apress where they throw out great Lisp books for 6/7/8 Euro printed or digital. Subscribe to r/lisp or r/common_lisp and you will get the news.