There are taxis in Cortona, but they don't just roam around like in a large city such as Rome. If you want to get a taxi, your best bet would be going to a very crowded and popular place, or finding the number and calling ahead, then asking for a pick up at a pre-determined location. The cost for a ride in a taxi won't be too expensive, but if you continue to use them you will end up spending quite a bit, especially since the euro has more value than the dollar. However, you really shouldn't need to use taxis in Cortona too much anyway. It isn't that small of a town that you could walk from end to end, but you won't really need to be going all over the place in taxis either. Much of the attractions are condensed in areas close by, so you could walk around if you needed to. If you want to rent a car, you can do so from either the airport you fly into(Rome, Florence, Milan), or a train station if you use the rail to get to Cortona. The roads in Italy aren't too bad, although once you get out in the country they are not as good as near the more built up areas. Driving through the Italian countryside is a very pleasant thing to do though.