The meetup group gets a 20% discount for this event. Just enter the code "IDW" at checkout (it is case sensitive).
Tickets here: https://www.eventbrite.com.au/e/roxane-gay-christina-hoff-sommers-feminist-sydney-tickets-54833325954
Also, depending on how many of us come, the organiser said he would give us a meet and greet with Chistina Hoff Sommers.