The option to not require billing information is available at the plan level for plans configured with free trials. When you are creating a plan and select a trial length, you will be presented with an option to configure your plan to require or not require billing information at the time of sign-up. A plan must include a free trial to be able to configure this setting. You do have the option to edit any current plans with trials to not require billing information at sign up as well.
Free Trial coupons are a great way to offer your customers an opportunity to try a new subscription plan for free. Unfortunately, the option to NOT require billing can only be configured at the plan level, for those plans with free trials.
More information on Cardless Free Trials in our docs here here: https://docs.recurly.com/docs/plans#section-cardless-free-trials
Free Trial coupons here: