Generally not required for stays of up to 90 days (or at all for EU nationals); some nationalities need a Schengen visa.
Most articles you take into Sardinia for personal use can be imported free of duty and tax. The following allowances apply to duty-free goods purchased in a non-EU country. In addition you can bring in other products up to a value of €430.
Alcohol 1L spirits (or 2L fortified wine), 4L still wine
Other goods 60mL perfume, 16L beer, 200 cigarettes
Cash Up to €10,000