Can we rent a car in Spain and drop it off in Italy, we will need it for 3 weeks? What do you recommend?
You can but the drop off fee in another country from the one you rented it in would be very high.
For three weeks leasing might be a better choice than renting. See Renault's Eurodrive program at www.renaultusa.com or Peugeot's Open Europe program at http://tinyurl.com/654ptr.
I wanted to rent a car in Italy and drop it off in Germany and the drop off charge was $735. Euro! With the conversion that is more than the round trip ticket to get there. We found a drop off place very close to the border and have made arrangements to rent another car as soon as we cross the border. Can you rent a car in Spain, drop it off close to the border and rent again once you get into Italy? You should be able to do that if the towns are large enough to have a car rental agency. I went to the car rental and checked locations and that is how I figured out a way to get from one country to another. Some the of connections are not perfect, but it will be an adventure.