The final season of 'Stranger Things' is reportedly Netflix's costliest project with $50 to $60 million spent per episode, reported Puck. Each of the eight episodes has reported run time of 90 to 120 minutes, taking the total budget to $400 to $480 million. This surpasses 'The Witcher' season 4's $221 million budget where each episode cost around $27.6 million.