When my daughter was in elementary school I used to do a table at their Holiday Fair. I sold "Breakfast in a Bag" - a clear bag with jam or jelly and homemade English muffins or a miniature loaf of nice bread. That always went over well. There were always lots of parents (usually Moms) with cookies and cake but rarely bread. Another thing you might consider are homemade dog biscuits - there are lots of recipes out there. In my experience putting an item in a clear treat bag with a bow makes it more sale-able that the same item just sitting on a table.
(My nephew lives just outside of SanDiego, in LaJolla. I am pretty sure that his daughters' school have a holiday fair also - Probably not the same one?)
