How difficult is it to use the metro system in Rome and Paris? In February, we will be spending 4 days in Rome and 5 days in Paris. Can we purchase in advance? If so, where?What would be the most economical way to purchase these tickets?

Post this on the Europe forum.

But...Paris is easy and good. Just buy the tickets when you're there. If you're there awhile buy the Crate Orange. Bring little passport photos from home to put on them. Rome's really doesn't go anywhere useful. (It's hard to dig underground there - too many ruins.) You just walk in Rome, that's what works best.

Not Crate Orange...Carte Orange. And you buy them in the subway stations.

Agreed. You will use Rome's very little. It is good for the Colosseum, not too bad for the Vatican, and can help with some churches and other sights on the perimeter of the central historic area. Buses can be very useful although sometimes confusing.

You can buy a pass in Rome that will be good for the metro and the busses. The 3 day BTI ticket is 11 Euro and the weekly CIS ticket is 16E.
www.atac.roma.it