A better idea is to offer a free, limited version with no support and premium versions with support. That way your time is focused on those willing to pay and anyone who needs it free has to find someone to help when they get stuck. That gives them an incentive to upgrade while still making your SaaS visible to new users. I think Trello has it right; the free version has us onboarding hundreds of new users for them and teaching them to use it and the paid version is worth paying for if you need to control your users.