@serinuntius - unfortunately the organisation apps are charged on a per usual basis as they are not considered PUBLIC apps and therefore have a specific range of people that can access them. limited per registered users by a charge is how Glide restrict organisation apps being abused and used widely with only one $8 being charged.
If your users don’t need to edit the app infrastructure the better financial decision would be to upgrade the app to pro and then create your own whitelist to restrict the access rather than paying $8 per user (which will become expensive if your user base increases!)