I'm going to Florence for a week in a few weeks time and would like to visit other places in Tuscany on day trips - Siena, San Gimignano and Lucca. I've seen several companies offering tours online that you can book before going and they say they are cheaper if you book beforehand. I don't really want to do this - want to wait til we get to Florence before deciding what days we want to go, depend on the weather, how we feel and so on. Are there plenty of places to book tours in Florence itself and are these expensive or about the same price as ones offered on the internet?