$50, but.......catering was by the Spit Roast Company, and our speakers were free (ex-members).
From memory, our advertising was free as well - it all just went through the "old-boy" network.
This was in 2009 as well, so let's add inflation in to that :)
$50 seems skinny now - if we did the same again, I'd be nudging it up around the $70 - $80 mark