It's incredible how cheap it can be to travel within Italy today, with some advance planning.
Venice/Naples is a fairly popular route, and here there are some really, really cheap travel options.
Looking at the situation today, here are the current options for cheap travel:
AIR TRAVEL
The 75-minute flight is clearly the fastest way to travel. There are flights with Easy Jet, Meridiana and Air One/Alitalia.
ABSOLUTELY CHEAPEST FARE:
13.49 Euros on Easy Jet.
Other fares: 29 Euros on Meridiana and 48 Euros on Air One/Alitalia
NOTE: Air fares vary widely according to season and flight times. The cheapest rates usually require booking well in advance. Also note the surcharges for luggage on the discount carriers, which can significantly add to the total cost of travel.
TRAIN TRAVEL:
The Intercity Night (ICN) train "Marco Polo" departs Venice S. Lucia at 23:30, arriving in Naples at 10:00 the next morning. A reserved seat in second class costs 35.20 Euros (not recommended); a bunk in a C4 quad couchette compartment costs 51.90 Euros; while a bunk in a twin sleeping compartment costs 71.10 Euros. All fares quoted are for the advance-purchase "AMICA" ticket. The "regular" fare is 20% higher.
NOTE: Trenitalia no longer offers the "Excelsior" class luxury sleepers on this route. Too expensive and not enough demand. Rest rooms are located at the end of each railcar. The twin sleepers (but not the quad couchettes) have a wash basin with running water.
(continued)