The cost of living rates in Florence are much like the rest of Italy. The Euro is the recognized national currency, and the current exchange rates apply. You can have your currency exchanged to Euros at any bank. Typically, the charges for a one liter bottle of mineral water will be $1.43 in US dollars or EUR 1.
 A three course meal with wine or beer will typically cost you $25.73 US or EUR 18.
 Again, you can find currency exchange information from any Florence bank, or possibly from your hotel upon arrival.