Italy is part of the Eurozone, so the common currency of the European Union, the Euro (?), is legal tender in Italy.
Italy is quite an expensive country. It has many luxury hotels and posh restaurants. It may cost ?40.00 a day if a person self caters, stays in hostel, avoids drinking and doesn't visit too many museums. However, staying in a comfortable hotel, eating out regularly and visiting lots of museums and galleries, may cost at least ?150-200 a day. Hiring a car may double expenses, so one should visit with sufficient funds.
All the bills include the service charges, so tipping is not necessary, although it is widely customary in restaurants and in hotels. Round up the bill to the nearest Euro 5 or limit the tip to 5% and everyone will be happy. Tipping taxi drivers is not necessary, but a hotel porter may expect a little something. And unless otherwise stated, prices are inclusive of IVA sales tax (same as VAT), which is 20% for most goods, and 10% in restaurants and hotels. On some products, such as books, IVA is 4%. If you're a non-EU resident, you are entitled to a VAT refund on purchases of goods that will be exported out of the European Union. Shops offering this scheme have a Tax Free sticker outside. Be sure to ask for your tax-free voucher before leaving the store. These goods have to be unused when you pass the customs checkpoint upon leaving the EU.
If you plan to travel through countryside or rural regions you probably should not rely on your credit cards, in many small towns they're accepted only by a small number of shops and restaurants.
Remember that in Italy (even during the winter months) it remains very common for shops, offices and banks to close for up to 3 hours during the afternoon (often between 12.30 and 15.30). Banks, especially, have short hours with most only being open for about 5 hours a day.