Web Advertising (Facebook, Youtube, Twitter etc.): Free
Bake Sale: $25 (Considering we have most of the ingredients)
This graph shows how much money we need to spend on each thing. As you can see we do not need to spend money on the Blog or the Web Advertisements, but we need to spend money on the bake sale. the cost shown on the graph is not the guaranteed price needed for the bake sale. This is how much money will probably cover the whole cost and if we have some extra money we could use it as a donation or use it for the bake sale (like buy some extra whip cream or some chocolate icing.).
The reason we are spending so much money on the bake sale is because we know it's going to get a lot of donation money. It takes $0.30 worth of ingredients to make 1 muffin. If we mark the price up to 5x the amount of money it takes to make each muffin, we can sell a muffin for $1.50. Now let's say that our whole class and a whole bunch of people all over the school will buy 1 muffin, we shall have over $100's of dollars to donate. (If 70 people buy 1 muffin we shall have over 80 dollars, $84 to be exact.) Also we could do two bake sales, overall cost of about $60 worth of ingredients, then we could not only sell muffins to the students, but to relatives and parents after school or maybe before school.
Also, we could post news about our bake sale on our blog and maybe people who live near by could buy a muffin or two, just saying. And if we do then people will actually start taking us seriously and maybe they might even donate some money, to our cause.