Pisa is not an expensive city, especially in comparison to other popular university cities such as Rome, Milan, Bologna or Florence.
The average rent for a single room in a shared apartment is between 300 and 350 euros per month, and regarding food there are many kinds of supermarkets with different costs.
Also, a Foundation Course student may eat twice a day in one of the university canteens with a cost of around 5 euros per meal, which includes first, second course, side and fruit/dessert.