I am certainly not arguing that activist events must be free. Obviously costs have to be recovered.

I am arguing that activists shouldn't work with the national monopoly ticket vendor (TicketMaster/Ticketweb) or with a corporate concert promoter (Pokerface LLC). Dropping Ticketweb and Pokerface would probably have made the event affordable. The next step would have been to hold the event in a school auditorium or at a library, where the room rental cost would have been negligible. When you want to involve as many people as possible, you make these sorts of concessions.

Regarding concerts, I don't go anymore -- precisely because the ticket prices have risen so high.