That must depend on the school, their budget, number of students and their socio-economic status.
In my son’s school (in a poor, urban school district) they raise money to help the kids afford to participate in school activities and trips (prom, senior trip, band trip, etc)... so the goal is that the kids can afford to participate. Some fundraisers only bring in a few hundred dollars because there is not a large base of parents/others who can put extra money into fundraising. I am aware that this is vastly different than private/suburban school fundraising and likely does not answer your question.
I think when my kid went to private school, parents were expected to raise around $1000 per year through fundraiser participation. It’s been many years, though… so I’m not sure about the amount. The school happily accepted volunteer hours in lieu of fundraising dollars for the poorer families.
The profit margins range from 20–50%, depending on what is being sold.