Things to do when you're broke.
The intention of this edifice was to eclipse the original St Peter's in Rome, however the then Pope decided this was not such a good idea, even though it was dedicated to the patron saint of the city, and canned the completion not long after 1392. Inside you can watch the sundial laid out on the apse floor, timed by the ray of sunlight falling through the roof. The admission is free and actually offers free guided tours on Tuesdays, Thursdays, and Saturdays at 11.30am.
Time to walk off that huge bowl of pasta. The Sanctuary is an 18th construction up the hill 3.5km from the centre of town and you can count the 666 arches as you climb (any significance??) to the top. St Luke is said to be responsible for the image of Mary, which is brought into town for a week every May. The view from the top is also spectacular and a nice break from buildings.
Looking for a bit of spirituality? The majority of churches, or Chiese, are open to the public and free but they require a respectful level of dress. As a rule neck to knee coverage and no bare shoulders or belly buttons. It also pays to come back later if a service or mass is in progress.