Within Campania the public transport has a unified ticket system called Campania Unico. [http://www.unicocampania.it/index.php?lang=en] Tickets are organised in zones which means that with one ticket you can travel within one or more zones. The zones radiate out from the centre of Napoli, and allow you to travel within a zone or between zones, with a maximum time limit for the journey. The idea is that you can purchase a single ticket to travel from a zone outside Napoli to the centre, or vice-versa. Included in this system are generally national trains (also to Paestum, the underground in Naples, the Funicolare in Naples, Sita buses along the Amalfi Coast, the Funicolare on Capri, Bus of Ischia the Circumvesuviana that goes also past Pompeii and Herculaneum but not ferries. The advantage is not only that you can get tickets for different kind of vehicles, but you could also buy tickets in advance for areas where it is difficult to find a ticket office such as Paestum, as the tickets start to be valid once you stamped them. You should stamp the tickets each time you change vehicle, but be aware that the tickets are only valid for one train, Metro or Funicolare journey. It is possibly also cheaper to buy a bunch of 'one zone' tickets than each time a new one. But careful: some tickets are locally bound (only in Naples, for example). If in doubt, ask when you buy your tickets. (Campania Wikitravel)