Update 10/6/19: Deal is now live, a full list of deals can be found here.
Target’s new rewards program ‘Target‘ Circle will launch on 10/06, to celebrate they will be offering 15% off all movies & books until October 12th (excluding new releases, pre orders and clearance items). According to this Slickdeals post you’ll be able to also stack this with 5% on REDcard, although normally you have to choose between Target Circle & REDcard, so that will depend how this discount is applied.