Shahiem I respect that decision.
But, I think messaging feature, at least the basic ones, should be free and paid for some advanced feature.
Heck, those popular messaging system are free to use (with limitations, of course), ehem Slack ehem Discord ehem.
But, it is just my point of view. I just don't see it working with only paid version, most especially, for the community.
Of course, it's your decision. I am not holding you back nor discourage you. Just trying to give you options/model that will work best for you and for the community.
I am sure someone else will make something I described above. Lots of possibilities in Flarum ecosystem.
Edited to clarify my point of view.