That depends entirely where your starting point is. You can get flights from the UK for only a few pounds sometimes and it is never expensive if you travel by one of the Budget Airlines Like Ryan Air. You could do the trip for well under 100 pounds.

Going....not so much from Europe but pricey from North America. Once there, however, that is where it takes lots of money to thoroughly enjoy yourself. I just had a friend tell me it was almost USD $40 for a breakfast at McDonalds in downtown Paris.

Well, you need to take into consideration where you are traveling from, what time of the year you are going, and what kind of accommodations and food will you want to eat while there. I have been to Paris but not Rome. We stayed at a hotel within walking distance of the Eiffel Tower for $135 a night, it was small but nice, and on a local market street called Rue Cler. We went in August, and my ticket from Virginia to Paris, then Brussels back to Virginia cost a total of $1700. In the winter it is less expensive, of course. When you eat, keep in mind that a lot of restaurants in Paris charge different prices depending on where you sit (ie. it's more expensive if you sit outside or away from the bar area), and yes you can find reasonably priced restaurants, although I recommend getting away from the tourist sites for the best food at the best prices. The Rue Cler market area is really my recommendation... great restaurants, great location, great hotel (Grand Hotel Leveque). One night my husband (bf at the time) and I just walked down the street, bought some bread, cheese, wine and meats and went back to the hotel room and had that as dinner. Best meal I ever had!!!!!!!!

Go out to travelocity.com or expedia.com and enter the info - you can get a really good idea on hotel and airfare from that. :) Have fun if you go!