Hey Drako, i'm really glad you're liking the asset so far!
in summary it works like that:
Free version: you can freely use this version for any non commercial project and i don't have any problems with open sources type of projects as long you add credits for the original asset page.
Paid version: You can use it with any commercial or non commercial project, but you may not redistribute the asset in any way, so if the assets are available in any other source which isn't the official asset page or sources with permission for it, it is not allowed.