Number one, this is like my favorite place ever. I'm a bargin food finder. I go crazy when I find something delicious that is easy on the budget.
I would always get a roast beef, harissa and lettuce sandwich there for like 2.5 euros. It was awesome and filling. The turkey brie and sun dried tomatoes was another great one for around 3.20 euros.
This was on the way from Santa Croce to the Duomo. If you are there check it out.
AND if you are there, see if you can't find out what brand they use of Harissa, that stuff was like crack. I would be forever grateful.