I see Italians buying their wine at the local grocery store or supermarket, although the butcher shops often have the higher quality wines. There are usually enotecas (high quality wine stores) in most areas, higher prices there.
In some small towns there are places where you bring your used bottles and they refill them for 70 cents to €1.25 from 250 liter drums.

Generally the house wine in good local restaurants is very good. I know some trattorie in Tuscany where the house red is a rosso di Montalcino, and they'll sell you a bottle for €8 to €12. Not a lot of point in getting fancy on the wine list in those places, the "generic" house wine is often the best in the house.