It depends on the purpose and nature of your trip. There is no set amount for the Schengen zone, each country is free to determine their own requirements; sometimes they even list this on their foreign mission / embassy websites.
For example, the Netherlands:
"You also should be able to prove you have sufficient funds for your stay in the Schengen area. In the Netherlands this is a minimum of € 34 per person per day. In some cases, such checks may result in a refusal for the visa holder to enter the Schengen country or the Schengen area."
For Italy, there is this handy PDF (in Italian) which has on its last page a table that lists the fees for the lenght of stay, and number of travelers.