We walked past this small shop around the corner from the Accademia while we waited for our David reservations. We had to return because it was filled with students. A crowd of students usually mean that there is great food for cheap. So we went back, and possibly had the best panini of our trip. We had sliced Olio foccacia, toasted with fontina cheese, topped with speck (smoked prosciutto) and spread with truffle sauce. While waiting we had a glass of wine out on the sidewalk. It was all excellent and incredibly cheap. Definitely a don't miss when visiting Florence.