Hi Enrique,
Thank you very much for your kind words!
Well, the answer can be both yes and no – it depends on the use. This is the statement of Envato market regarding this topic.
Basically, if the subdomains (or separate subsites) are simply used to organize the content around the same subject, then one license is enough. If the subsites are of different topics, then separate licenses should be purchased.
Unfortunately our seller platform does not offer any multi-use or bulk licenses.
I recommend buying one – then trying it out across the multisite installations, to make sure it works correctly. You can still install the plugin on as many sites as you need. Then purchase the remaining number of licenses you require, where the plugin is used an working fine.
The lite version is limited in this case unfortuantely, it does not have the taxonomy filter part implemented.