My girlfriend and I are getting the Eurostar train to France next month, and we need to get a connecting train from Paris to Tours. I know I can book the train in advance, but can anyone tell me if it's cheaper to book in advance from the UK (in case of any targeted pricing of tourists), or whether turning up on the day to get a train would be cheaper?
Between Paris and Tours you can either take a TGV (highspeed train) or an "Intercités" (classical train). Both are cheaper when booked in advance. The full fare for a 2nd class TGV ticket is 65 EUR. Booked in advance it can be as cheap as 25 EUR. For Intercités the range goes from 15 EUR to 36.20 EUR.
You should also know that TGVs can sell out. If you are really unlucky and show up at a very busy day, there may be no more seats available.