If museums are your thing (if you’re going to Italy how can you not enter a museum or two?) save money by purchasing tickets online. You can also avoid the long wait at the museum by purchasing tickets in advance. This is well worth doing as it can be quite chaotic in Italy, not like the U.S. where everyone is all neat and orderly. Also, it’s just busy there!
If you’re going to Rome, purchase a Roma pass. They are good for entrance into two museums and unlimited public transport for 3 days from the date of activation. Use it for places like the Coloseum, and the Palantine Hill.
You can also buy a Roma Pass once you arrive at any of the tourist information centers. When I was in Rome last year I bought one for 25 euro. On the website they are 34 euro. I don’t know if that means they are cheaper at the TI’s? Try it and find out.