Travelling from most locations, it is best to book your flight to Pisa during the month of November for the best deal, although there are other times of the year which offer great deals as well.
In general, booking your departure to Pisa for a Thursday represents the best deal on airfare. Try to avoid a Friday departure to stay away from the highest prices.
Generally, when visiting Pisa, afternoon flights represent the best value. evening flights are likely to have higher prices.