GlobeWanderer, thanks for the detailed report. I looked back through my receipts and although it doesn't specify, I believe it was indeed a Smilys fare. I would guess that the difference in price is due to a fare increase in the past few months. I know that I had to look around a bit and that I couldn't find the fare for every train, I think they are fairly limited in number. In any case, it was a great deal. I believe that the summary of available trains that I got to fairly early in the booking process (via SNCF) showed the lowest fare for each journey and that I had to specify "return" for the Smilys fare to show up. When I'm seeing high fares for a one way ticket I always check on return fares, since I frequently find them to be less expensive.

BTW - a great tip is to specify that you're in France when booking, even if you're not. If you say "US" you'll be redirected to the very expensive RailEurope fares. If you say "France" you'll find that most - but not all - journeys will allow you to book online and print your own ticket, making your location moot. If for some reason a particular journey doesn't have this option - when they do and don't remains a mystery to me - you'll see this and have a chance to bail out before you complete the purchase.

In theory, you can also book and pick up the ticket at a machine at the station. I've never tried this being wary of the fact that US credit cards seldom work in those machines. I did recently read that if the machines don't work an agent can also print the ticket for you.