ooooh….I LOVED Florence…I actually wished that my friends and I had stayed there more than in Rome or Venice. At any rate, for breakfast, I’d recommend going to the Mercato Centrale…there’s stalls in there with fresh fruit and the such, and there’s a cafe upstairs where you can get a good espresso shot for just 70 cents euro. :) Then you can wander around the San Lorenzo flea market just outside of the place. :)
http://www.aboutflorence.com/typical-markets-in-Florence.html