In order to rent a car you will need a passport, a credit card and an international license with at least 1 year of driving experience. A driver should be older than 21 (some companies require the age of 23).
Maggiore, Kemwel Group, Auto Europe, Europe by Car are the largest car rental companies.
Besides the rental fee, some companies require a deposit equal to the sum of the rent. The longer the rental period is, the less is the fee per day.
Once you have a car, make sure it is in good condion and has an insurance. The insurance usually doesn’t cover stolen cars. To prevent this situation, you should buy additional policy for 10-15 euro per day. When you sign a contract, ask the manager to explain in detail each point of it. Also make sure that VAT (18%) is included in the cost of the rent.
You should take care of gas for your car in advance. Many gas stations in Italy close after 19:00; and lunch break lasts for 2-3 hours. Sunday is a day-off. The exception is made by gas stations located on the main routes; they work 24 hours a day.
In many cities you can also rent a bicycle or a motorcycle. You will need a passport to do it.