Hi everyone,
Different chapters are looking into organizing next years hackathon. One of the recurring questions is how much it costs to organize such an event. To make it easier to answer this question we published the budget of the Amsterdam hackathon at https://www.mediawiki.org/wiki/Amsterdam_Hackathon_2013/Budget . I believe it's the intention to also publish the budget of this year (Zürich) and 2012 (Berlin). That should give quite a complete overview.
One note of warning: You might have different costs than we had. Take for example the internet and wireless: We didn't spend any money on that.
Maarten