Multisite/Network Licensing Fee

Your website says Clean Education Pro costs $49. Is that a one time fee to be used on multiple sites? Or is that $49 per site? Or is it $49 per site and/or per network site? My client currently has a WP website that is a multisite/network. The primary site is the administrative/HQ of the organization, while the 8 different locations are given a subsite. Thanks!