As far as the ambulance services go...they have paid staff that are employed just to fund raise. Normally on that scale it's through Banks, Business, etc.
On a smaller scale the Ambulance cadets (Kids group) do fund raising so they can go to First Aid competitions and camps, etc.
The most popular form of fund raising in New Zealand is 'Sausage Sizzle'.
The large Department stores usually offer a space in front of their shops (normally on a weekend).
Most of them also supply the BBQ, as a form of sponsorship to the groups fund raising.
Another place to set up is at Sports grounds.
The Sausage sizzle is basically a Sausage rolled up in a slice of bread, with Tomato sauce (ketchup), mustard and cooked onion. They normally sell for $1.00 - $2.00.
Just to give you some idea. My daughter's High School Choir were fund raising last year to go to Australia. They would make on average $400 in a day.
You may already have Sausage sizzles in the USA.I don't know. But they are a sure winner for fund raising here.
http://www.youtube.com/watch?v=1EWnC7CYMEc .....Please note these guys had a bad day. Was more to show what they were selling.You have to promote your product! lol.
Cheers Enjoynz