i have thousand of customer and they raise tickets thru support/helpdesk. But cannot see the status of the tickets raised by them. 

I want give them access as portal user. Does these access will result is paid license or not. I do not want to take any paid license as those will be in thousands but want to increase the happiness of my customer as they can track or check the status of all there issues from the screen and not calling again and again which result in lots of waste of time of my support team.