Avellino is a city in the Campania region of Italy.
By bus from Capodichino international airport (Naples). Ticket is only 3.4 euro. You can go also by taxi for "special price only for you" - 100 euro. There are some car rentals directly on the airport.
By bus from Naples Railway station. 1 hour ride.
There are two motorway accesses along A-16 (Napoli - Bari)
City is small enough to get around by foot.
There are some buses. Find a plan online here:  (unfortunately only in Italian). Plans on stops are burned by sun (totally white - you cannot see anything). You must buy a ticket in a stand and it's valid for a certain timespan. Google maps route finder gives good approximates for walking distances and walking times around a city.
Viva! Hotel in the town center has reasonable price compared to the competitors. Staff is friendly and service quality stands for the money you pay for accommodation.