While having an Italian rail pass, also called a Eurail Italy pass, may sometimes be more convenient, it doesn't always save you money unless you are taking several trips between major cities, traveling long distances, or traveling to Italy from another country. If you buy an Italian train pass you will still have to make (and pay for) seat reservations on high-speed trains.
Regional trains in Italy are inexpensive so using a rail pass for regional trains and even for most Intercity trains is not cost effective. You can check the price of individual tickets on the Ferrovie dello Stato Italian rail site and check or buy Eurostar train tickets for your route on Select Italy's Train Tickets page.
Check prices of or buy a Eurail Italy Pass.
There are many types of European rail passes available including passes good for train travel in a single country or for multiple countries. Train tickets in most other European countries are generally more costly than those in Italy so if you're traveling by train in another country in addition to Italy you may want to consider a two-country pass. Our Europe Travel site has more information about Rail Passes in Europe.