Fundraising is not necessarily film investment. An organization or church that sells candy or has a bake sale is exchanging a product for money, so the buyer does not expect to get anything more than what they purchasing. When someone gives you money and gets nothing in return except a promise from you that they are part-owner in an entertainment product, then things are very different.
There are a number of books on this subject, so I'd do a tour of
AMAZON.COM (this links helps Script Nurse ... we're still hoping to break the $8/year revenue barrier).