The reality is that funds do need to be raised because budgets are often times inadequate to deal with all of the needs that a school or school district has.
There are a lot of different ways that vendors can reach out to a school: My personal preference of hearing about a particular product would be going to a trade show, and the initial contact with a postcard. My second would probably be direct mail to the school, third would be an email (knowing that we get hundreds of emails a day). My last choice would be personal contact just because of the time commitment of a sit-down meeting.
The relationship with the vendors is the key, and they need to follow through with the promises that they make and be predictable. Having a program that causes less impact to the administrator and faculty with the company stepping in and taking on a lot of the responsibility makes your program more desirable; good timing in getting in touch with the school is crucial as well. As far as the type of fundraiser or product goes: If it’s a food item, then it needs to be healthy, the product needs to have value, and the fundraiser needs to be efficient, with a high return on investment.