Don’t have a free plan unless serving the people who use your free plan is truly part of your mission. If you’re thinking about your free plan just as a step to a paid plan, you’re unlikely to build a successful freemium model.

A good free to paid conversion rate is 3-6%, and this means that 94-97% of users on the free plan will never pay. If you can’t appreciate and enjoy serving those folks, and truly build something of value for them, I don’t think you’ll make a freemium model work and you should just have a trial.