hey rambleon, according to the program description on http://www.amma-europe.org, all events with Amma are free of charge, donations for Amma’s charity works are however welcome.
(…of course everyone would agree with me that it’s not to see as a kind of "touristic event", but reserved for those who are interested in Amma’s teachings)
I only found German program details on that site, but maybe you also find English ones. If not, I’ll surely translate it for you 