Here's a breakdown of what we spent, by city (again, costs are for the two of us):
Venice (Day 1):
Train tickets from southern France to Turino to Padova (near Venice): 107.00€.
Venice (Day 2):
Train ticket into Venice from Padova: 2.90€
Entrance to Ducale Palace: 26.00€
Lunch at a restaurant: 30.00€
Train to Padova: 5.80€
Venice (Day 3):
Train into Venice: 5.80€
Vaporetto ride: 6.50€
Train into Padova: 5.80€
Florence (Day 1):
Train from Venice to Florence: 46.00€
Hostel (Ospitale delle Rifiorenze): 32.00€
Bus fare: 2.20€
Train tickets to Pisa: 25.00€
Florence (Day 2):
Entrance to the Dome: 16.00€
Boboli Garden Entrance: 10.00€
Florence (Day 3):
Entrance to the Uffizi: 10.00€
Siena (Day 1):
Train from Florence to Siena: 12.60€
Hostel (Camping Colleverde): 45.00€
Bus fare: 2.00€
Siena (Day 2):
Entrance to the Cathedral: 6.00€
Bus fare: 2.00€
Mantua/Ravenna (Day 1):
Train from Siena to Faenza: 22.70€
Mantua/Ravenna (Day 2):
Mantua/Ravenna (Day 3):
Train tickets Ravenna to Mantua: 21.00€
Entrance to Palazzo Te: 10.50€
Train tickets from Mantua to Ravenna: 21.00€
Mantua/Ravenna (Day 4):
Naples (Day 1):
Train tickets from Rome to Naples: 21.00€
Hostel (Hostel Pensione Mancini): 32.00€
Naples (Day 2):
Train tickets from Naples to Pompeii: 6.60€
Entrance to Pompeii: 10.00€
Train tickets from Pompeii to Naples: 6.60€
Naples (Day 3):
Train tickets from Naples to Sorrento: 7.20€
Bus tickets: 2.20€
Train tickets from Meta to Naples: 5.80€
Rome (Day 1):
Train tickets from Naples to Rome: 21.00€
3-Day Metro Pass: 22.00€
Hostel (Camping Tiber Roma): 22.00€
Rome (Day 2):
Entrance to Colosseum, Forum, and Palatine: 7.50€
Rome (Day 3):
Photos with Gladiator: 5.00€
Rome (Day 4):
Entrance to Vatican Museums: 23.00€
Metro tickets: 8.00€
Rome (Day 5):
Train tickets to the airport: 28.00€
Total cost of trip, (excluding random expenses, such as: souvenirs, gelato stops, and bottled water): 1,363.44€, or $1,716.43. Average cost per day, including lodging, food, transport, and all admission fees: 68.17€. Not bad at all for two people! So how did we do it?
General Money Saving Tips:
1) Couchsurfing: For those who don't know, Couchsurfing is a free database of hosts around the world who offer a free place to sleep to travellers. It may sound a little shady, but serious CS'ers have their identity verified as well as a ton of personal references from travellers who have stayed with them. We weren't too lucky in our searches, as we only found a CS'er in Padova to host us, but still, three nights of free lodging is pretty awesome! The best part of this is the cultural exchange. Our host cooked for us, took us to hard-to-get-to sites nearby, and gave us a wealth of information about visiting Venice. And because we were CS'ers, we were able to stay one night for free at our hostel in Florence! It also helped that our friend Meagan hosted us at her place for four nights. Thanks to her, we were able to save a bundle on lodging, got a chance to cook in her kitchen, and, most importantly, got to see a familiar face from home!
2) Regional Trains: In Italy, fast trains are expensive. The slow trains that require you to change stations several times during the course of your journey are much cheaper. Sure, it was a pain in the butt with all our luggage, but it was worth the money we saved. Also, the rail passes that exist are NOT worth it if you want to travel cheaply. If you're concerned about saving time as opposed to money, these work well because you can travel on the faster trains, but the expense wasn't worth it for us.
3) Campsites: These are usually located a little bit out of the city, but it's not impossible to reach them, just a little inconvenient. They also are more likely to have a swimming pool, laundry facilities, and their own market, bar, and restaurant. And of course, they're usually cheaper than hostels or hotels located in the city! Sometimes they'll even have kitchen facilities so you can prepare your own food, a double discount bonus. You can find some great deals on HostelWorld and Bookings.com.
4) Being under 26, a student, or an E.U. teacher: One good thing France gave us was our teacher cards, which scored us all sorts of discounts at museums around Italy. Sometimes, they also offer discounts for students or those under 26 who live in Europe. Even if you're just studying abroad, the visa in your passport is often enough proof to get you this discount.
5) Grocery Stores: Know where they are. One of the first things to ask when checking into your hotel is "Where's the nearest grocery store?" Here, you can stock up on bread, meats, cheeses, and most importantly, alcohol. We usually ate at least one meal a day from a grocery store, and it saved us tons of money.
6) Free water fountains: These abound in Italy, France, and I imagine other European countries, if you know what to look for. Much cheaper than buying bottled water, perfectly safe to drink, and has the added bonus of allowing you to drink from a dog's snout faucet or a gargoyle shaped fountain.
7) Street food: While it can get tiresome, eating slices of pizza or a quick panini is much cheaper than eating in a restaurant. Basically, if you don't need to sit down to eat it, it's cheap. I'm talking fat pizza slices for 1.50€, paninis for 2.50€.
8) Walk: Instead of taking the metro, tram, or bus, walk around the city. It's a much better way to see the sights, get a feel for the city, and save money in the process. Alternatively, you can try your luck by hopping on public transit without paying. Conductors rarely check your ticket, though the fine is hefty if they catch you. To save on transport money, book your hostel near the train station so you don't have to pay money for transport to and from with all your luggage.
I hope someone eventually finds this useful, and maybe some of you now have the desire to travel, seeing how cheap it can be?