Salerno-Tunis
From Salerno (near Naples) you can take the ferry from Grimaldi Lines to Tunis. This is the only company operating this route.
Ferry to Tunis and Salerno
The ferry connection (Salerno-Tunis) departs 2 times per week. The minimal price you could expect in local currency is about €44. However, ferry prices rise as the boat fills up, so it is best to book early and compare prices for different departures.