Rent a car and stay in the countryside instead of Florence itself. much nicer places, much cheaper. That's what I do.
Driving within Florence itself is not easy because you have to watch out of the ZTL or risk hefty fines. Parking is also not easy because it's limited.
So when I want to visit Florence, I park at a big supermarket outside of town and take the tram in. Visits to Florence itself is usually just a day trip. We spend most of the time in the countryside instead.