Yes! Postpone does offer a free trial.
You can sign up for Postpone for free using your email address, Reddit account, or Twitter account. You'll then have access to schedule Reddit posts or Tweets, which you can use to try out Postpone. You'll also have access to most Postpone features on the free plan.
Check out our Plans page for more information on what is available on the free plan and what is available on our paid plans.