Hi Bart – great question!
WooCommerce Tickets and in fact all of our events plugins are released under version 2 of the GNU General Public License:
http://www.gnu.org/licenses/gpl-2.0.html
So yes, they are on a commercial footing insofar as automated downloads and support require users to purchase a license, which of course gives us what we need to maintain them and build out new functionality, but they are completely free and open source nonetheless 🙂
Does that answer your question?