Depends on where you're travelling, and when. The three-day-in-one-month France Railpass (second class) is a standard price at $227.00 U-S, offered by RailEurope, which is co-owned by the French and Swiss national railway systems. You might want to check out point-to-point fares for your intended destinations at http://www.sncf.fr/indexe.htm. Enter your starting point and destinations and see how much the fare is. Early-booking fares are certain to be cheaper, but they're non-refundable and non-exchangeable, so you're locked into those journeys on those days. However, even the regular fare may be cheaper, again depending on your itinerary.