Rent Car before I leave?

If I were you I'd check it out ahead of time to avoid unpleasant surprises. Renting a car in Italy isn't easy; there are wide variations in the hours of operation at different locations (some are not open on weekends), prices and minimum terms for rentals (often there is a 3-day minimum), insurance requirements, etc. If you pick up one place and return to another there can be a drop-off fee. And when returning in Florence, you will want to be VERY careful to avoid a location within the ZTL, as you may get hit with the fine even if you are just returning the car. - That said, we found the best combination of location, convenient hours of operation, and price (with no dro-off fee), by renting from Hertz. This was for a 2-day one-way rental between Lucca and Pisa airport (the airport location has much more liberal hours of operation than in-town locations). You might check AutoEurope and compare with Hertz and others before you decide.

I'm going to guess that 95% of people posting here reserve a rental car online before they depart, for reasons mentioned by Lola.

And for more info about the Florence ZTLs mentioned by Lola, go here: http://www.ricksteves.com/graffiti/helpline/index.cfm?fuseaction=readtopic&topicID=28422&page=2

Plus, if you can't drive a manual transmission, that might be all that's available if you don't reserve.

I would contact gemut.com, out of Oregon. I have used them twice and got the better price. It is worth a try.

I always check with Europcar (NOT Europecar, which just mimicks it). They are the most ubiquitous car rental agency in Italy. Use the local site (europcar.it) if you know the language, they have lower prices than the ones marketed for Americans. Remember: in Italy, it is compulsory to have Theft Protection and Damage Insurance, so all prices are quoted with that. No car rental agency is located within ZTLs and, if they are, their cars have waivers. What you SHOULD do is just basic "pay attention to road signs". Not all GPS take into account ZTLs when suggesting a route, but they are all well signed. Most people who get fined for ZTLs are hit in the pocket because they ignore everything but their GPS screens. I've heard of some folks who trusted GPS maximum speed info and were fined (harshly) by going over 90km/h in a roadworks' zone limited to 40 km/h. Just pay attention to the signs! Particular the mandatory ones!

The ZTLs are well marked (at least for natives), www.germantravel-info.com/graphics/ztlsign.jpg

If you can drive a stick, get one. They get better mileage and IMO more power out a the small engine......Diesel is another good choice. European diesels are great; they aren't loud, smelly nor is there vibration like you might expect. You would never know you're not driving a gas engine. Diesel is generally cheaper in Europe too, just be sure you know which gas you need before you drive off the rental lot.

I don't know about Italy, but for France we went through our local AAA and got a big discount.

Couldn't you reserve the car and cancel if you decide not to use it? That way you have the guarantee of the best price but can be spontaneous if your plans change.