How much would it cost me to go to Rome?

There are lots of guidebooks that can be useful for finding interesting things to see & do and to help you plan for the trip. Hit your local bookstores and browse the travel section. The actual price will depend on exactly where you're starting from, and when you come to Rome, the kinds of places you stay in, how long you stay, how you get around and what you see, do and eat. Generally, you can get by for around $100 (plus airfare) staying in cheap hostels and watching your budget. Hotels are going to be more expensive. Generally, the places I stay cost around 100 - 150 euro per night depending on when I visit.

Here are some resources that can help you plan and check options and current prices for your trip:

http://www.kayak.com/ - airfares & hotels; the explore function is useful for finding the less expensive places to fly into from your starting point.

http://www.skyscanner.it/ - particularly good for budget flights within Europe, but you can also use everywhere as a destination to do something like the explore option on Kayak. You may not need the airfares, but you can compare to the cost of the trains to get around.

http://www.fsitaliane.it/homepage_en.html - Train schedules in the event you want to take a day trip to someplace like Florence, Tivoli, Orvieto or Naples. You need to be aware that a railpass is almost always more expensive for trains here if you're going to exclusively travel in Italy.

http://www.venere.com/ - hotels/B&Bs - prices for the same hotel can vary hugely depending on the season and what local events are going on.

http://www.hostelbookers.com/ - hostels.

http://www.monasterystays.com/ - monasteries & convents that offer accommodations

You can also look into camping or couch surfing as cheaper alternatives for accommodations.

http://www.whatsonwhen.com/sisp/index.ht%E2%80%A6 - festivals, exhibitions and events

http://www.backpackeurope.com/ - information & advice

For sightseeing prices: check the websites for entrance fees for the museums & galleries you're interested in. I spend anywhere between nothing and 40 euro ($49) a day depending on exactly what I go to see when out exploring. For food, I spend around 25 to 50 euro ($31 to $62) for a meal, but you can eat for less. I was in Venice recently and paid 32 euro for lunch at Da Raffaele sitting at a canal side table with the gondolas passing by. Here in Italy, You can get a whole pizza for 8 to 13 euro ($10 - $16) or a pasta dish in the same range. Panini or pizza by the slice is less. For reference, a McDonalds McMenu classico (medium) is going for around 7.50 euro ($9.24). While you can eat cheaply most of the time, I would recommend getting a good local meal from time to time; that's part of the overall experience that it would be a shame to miss. When I travel, I like to try the local specialties and the good restaurants. Try the saltimboca or a pasta Cacio e Pepe in Rome.

depends on when and what you book. i suppose at the least you can get a flight for $800 round trip if booked at the right time. I usually spend around $60 a night there for a hotel, and that is with a shared bathroom, possibly near the main train station(termini)

Then maybe the equivelent of $50 a day on food and other expenses