Well, seminars cost money to organize, unfortunately. But I have been not unexpensive seminars recently. A weekend seminar with Tamura Shihan in France cost 20 Euros (18$) including 2 meals. We had 2 free of charge seminars at the Renbukan Dojo (Thai Aikikai) recently with Kobayashi Shihan and Yokota Shihan....
I will be attending a seminar soon with Sugano Shihan which will cost me 150$ including one welcome dinner but I'll have to pay the extra hotel, food and airplane tickets.
So it depends.