Hello,
I believe plans from Skype are the cheapest you can get. They have a calling plan for calling Italy landlines at around $8/month for unlimited calling. They do have a Fair usage policy for these unlimited plans, but still it’s a good deal.
Another option would be to use a regular calling service. Using Skype or any VoIP service requires a broadband Internet connection; if the connection goes down the phone service goes down. If you sign up for a regular service you can place calls using your current phone line. There are many such services providing low cost calling to international destinations. For example https://www.rebtel.com is a popular provider. Calls are made by dialing a local access number so being able to place free local calls is important.
Let me know if you have any further questions.