A couple of years ago we were in Italy. We bought a Europa prepaid card and had absolutely no trouble in Florence and a couple of towns. Even used it once to call between two towns. Actually, a few phones had the more popular keys (#) stick somewhat.

Are cards like this still used in France to call the US?

If so, are public phones (pay phones) still available on streets and/or various locations in Aix, Avignon and Paris?

I think prepaid phone cards are probably common in most countries of the world, you can definitely buy a prepaid phone card in France (telecarte), and there are still some pay phones around. There are always some in train stations, for one place, I guess lots of people need to call people from them (makes sense) and there is usually one near the ticket booth in metro stations.

You can buy them in all kinds of places, like supermarkets, the post office, news kiosques, tabacs and train stations/bigger metro stations.. In fact, you can't even use coins in most pay phones in France, so they would have to have telecartes unless no pay phones existed any more (which they do, even if not as many).

Prepaid cards to the US generally charge no more than 0.01€ per minute. After all, calls to the US from most land lines (but not in hotels!) are local.

Ok. Thanks.

Which is the best / most popular?

I don't know. I have a land line with free calls.

But the cheapest cards are usually things in the immigrant shops in northern Paris. Just walk north of Gare du Nord on the rue du Faubourg Saint Denis, and you will find 25 different card possibilities within 100 meters. All of the rates are listed on posters in the windows of the phone card places.

I think that most of the cards are sold for something like 7.50€, which contain more credits than a tourist could possibly use.

The cheapest ones are €5 on sale in tobacco shops.