Is Xen free to use?

Could you please clarify for me whether the use of Xen is free of charge? I understand that cryptocurrencies often involve transaction fees or other costs associated with their usage, but I'm interested in knowing if Xen operates in a similar manner. Is there a fee for simply owning or storing Xen, or are there any specific costs associated with sending or receiving Xen transactions? Additionally, are there any hidden fees or charges that I should be aware of when using Xen? Thank you for your time and consideration.