WP Camp Berlin 2012 --essentially a barcamp-style 1-day-WordCamp-- attracted ~200 people. Coffee, soft drinks and snacks were available for free all through the day. We served a warm lunch at the venue (vegan + non-vegan). The event received extremly positive feedback from the local community, so it became clear we were practically expected to do it again in 2013. At the second iteration ~300 attendees showed up.

Attendees were charged €10 for each event.

Our top sponsor packet was worth €1000. The one advantage we might have had was one of our team members was able to convince a local university (Beuth Hochschule für Technik) to host the event and sponsor all room costs at the same time. So our venue rates were down to a couple of hundreds of Euros for technology rentals (beamers, mics, technical staff). Catering could b provided through a service located in the same facility, so their transportation costs were basically zero -- an advantage they kindly forwarded to us in their extraordinarily kind offer.