In my experience, best solution is to buy a Vodafone sim card from Italy or Ireland.
Similar costs: 2€ + national tariff to get 50MB (per day) connection.
Whatever italian one is promoting its "vodafone passport mobile internet"
(
Reference): until 31/05 if you surf the internet you would pay 2€ for 100MB. No other charges
I think you can get on of those sims on ebay.