what would the price be for a dinner for two?
A dinner for two in Rome has a very variable cost based on the type of places. You can spend 60/70 euros in two in a restaurant not too expensive, without eating fish or drinking expensive wine. Otherwise you can choose a pizza and a beer in one of the most good pizzerie of Rome and pay around 40 euros. Don't go near the Vatican City or the Colosseum because there are tourist prices and food.