If you're flying to Pisa and travelling on to Florence, as many tourists do, get the LAM rosso bus directly from the airport to the Leaning Tower (Torre) before you travel on. This area is stunningly beautiful and can be done on a budget. There is no need to climb the Tower and the cathedral visit is free. The Baptistry, Museum and Camposanto (cemetery) are worthwhile if you have the time. If not, promise yourself a visit next time!