I've just found out that megabus runs in Bolgna, Florence, La Spezia, Rome, Turin, Siena, Verona, Venice, Pisa, Milan, Naples, Padua, and Genoa which is great. If you book early you can get a ticket for £1 plus a booking fee, I just checked you can go from Venice to Florence for £1 each way, and I doubt you can get any cheaper.
I have the perfect excuse to explore Italy again on a budget.
I have the perfect excuse to explore Italy again on a budget.