Cost of living in Modesto, California (United States) is 9% more expensive than in Arezzo (Italy)
This comparison is lacking data. It provides a decent comparison, but it is not yet reliable. It is based on 249 prices entered by 13 different people.
For example, you would need at least €2,623 ($2,984) in Modesto, California to maintain the same standard of living that you can have with €2,400 in Arezzo.