Transport in Rome is easy to use if you know the rules. There are different types of tickets, all of which you can buy from the ticket machines in stations, tabaccherie, bars and paper shops.
In order for the ticket to be valid, it must always be stamped at the begining of the journey or when entering the metro or on buses and trams. The ticket expires after 75 minutes.
The B.I.T. ticket must be preserved and shown on request to the control personnel on all means of transport.
If the validation machine is out of order the passenger must advise the driver and write on the ticket in pen; the time and date. If this happens when on the metro the ticket should be validated by the station personnel.
A €1,00 ticket is valid for 75 minutes for travel within the territory of the Rome municipality on buses, trams and one time only on the metro.
A €5,00 multibit (5 B.I.T.) ticket can be used 5 times even on different days (like 5 seperate B.I.T. tickets). It is valid for 75 minutes after each validation. It must be used only by one person.
A €4,00 B.I.G. (Integrated Daily ticket) is valid up to 12 midnight on the day on whichh the ticket is validated and gives unlimited rides on all transport within the Rome municipality. As with the other tickets, this must be stamped at the begining of the first journey.
A €11,00 B.T.I ticekt (intergrated tourist ticket) is valid up to midnight of the third day inclusive of that on which it was first stamped and for an unlimited number of jurneys within the Rome municipality.
A €16,00 C.I.S ticket (Integrated weekly ticket) is valid up to midnight of the 7th day inclusive from the date indicated by the customer as it's first day of validity for an unlimited number of journeys within the Rome municipality.
Obviously the type of ticket you choose to buy will depend on the length of your stay and the amount you plan to use the public transport system.
You will be fined up to €100,00 if caught without a valid ticket so remember to always stamp the ticket.
When on public transport always keep a close eye on your bag/wallet as pickpockets are very common. They are mostly small children and sometimes even pregnant women.