There are a number of ways schools can raise money for extra-curricular and even main stream activities. Michigan students in my lifetime have had the advantage of sports, music and the arts as a part of their standard education. I think it would be relatively easy to continue these functions, all the while maintaining fiscal responsibility.
Here are a few that I have thought of:
Advertising at lunch counters, hallways, bathrooms etc.. Signs, even approved advertising over the announcement systems.
Grade sponsorships. The student can get businesses or private individuals to pledge a small amount based on the student reaching academic thresholds
Paid school newsletters Cover all costs with advertising, and business sponsorships.
Advertising on issued school books could buy the books.
Things to avoid:
Fast food restaurants IN the lunch room, which promotes unhealthy eating habits. Those will develop well enough on their own.
Anything that indicates school preference of one brand, service etc.. over another, which could open the door for lawsuits