From Humans vs. Zombies Wiki
Method: Free, free, free.99
Description: Nobody pays anything, everyone gets all their own gear (Blasters, bandannas, cards, etc.)
Best for: Small games that you are haphazardly throwing with minimal effort (Still a lot of effort). This will attract the most players
Bad because: Can't have any cool props, pizza parties, prizes...
Method: Hitting up the man
Description: Get money from your student government. Every SG is set up differently but most schools have some sort of financial meeting that, with the right forms, you can attend and ask for money.
Best for: Medium sized games and people that want free money.
Bad because: Someone not connected to the game is calling the shots about what will be bought and what will not be bought. This means your not going to get the cool stuff. Also this can be a lot of effort depending on your school's rules.
Description: Selling things like tee-shirts, bandannas to cover costs.
Best for: Great salesmen or people with awesome skills in crafts.
Bad because: It is really hit or miss. Sometimes people will buy a lot but sometimes you wont sell a thing.
Description: Accept donations from players and anyone else you can snake money from.
Best for: People that are very persuasive. Keep games free but couldn't get money from student government.
Bad because: Lots of work for little output.
Method: Bank heist
Description: Rob a bank
Best for: People that own ski masks
Bad because: You'll go to jail
(The above is a joke. Do not rob a bank)