CBS All Access is offering a free month of access to the streaming service for all users with promo code Interrogation. You can select a free trial of Commercial Free or Limited Commercials plan.
Be sure to cancel subscription from your CBS All Access profile page before 30 days is up to avoid being billed if you don’t want to keep the service. CBS seems to be offering these free months on a regular basis, check back on this post for new promo codes.
h/t Doctor of Credit