If you want to provide a video for free and want users to sign up to access it, we recommend changing your pricing from Free to everyone to Require access. This will help you know who is watching your content and obtain their contact information.
Navigate to Content > Video, select the video you want to make free and then click Edit. Under the Pricing tab, click Require access, leave the Subscription plan as Choose plan, leave all the pricing options unchecked, then click Save. Add the free video to a freebie bundle.