In September we will travel from Luxembourg City to Colmar, France, then to Munich, Bolzano, and Venice. What is the best way to purchase train tickets to get discounted fares? In searching for Bolzano to Venice, the fare I am interested in seems to be the same whether booking early or the day before, but when I view the price, "other options" appears and it would seem two can go for the same price as one. Travel day is Saturday. Am I too optimistic?
The best way to buy train tickets is from the company operating the trains. Thta way you have no mark-ups and you know all trains are available on the website.
For example, Bolzano to Venice is Italian Railways: www.trenitalia.com
Except, you can only get discounts on high speed and long distance trains. If the train is a "Regionnale" (it will say when you look up the train on the website) there is no advance purchase discount and you can just buy tickets on the day at the station.
Yes, sometimes Trenitalia has a "two for the price of one" option on Saturday. It must be bought in advance and, if memory serves me, you can visualize it if you ask tickets for two persons together.
The direct regional and "express" trains from Luxembourg City to Colmar do not offer advance discounts on the French site; I would buy tickets in the station, instead.
Trains from Colmar to the German border or through Switzerland also don't have advance discounts, but if you are ready to commit to a date, time, and route, then you can book just the German portion of the train, such as Mannheim-Munich through the German DB train schedule link and use the same link for your next trip, Munich-Bolzano.
Germany also happens to operate and sell one direct train per day between Bolzano and Venice (at 15:30), otherwise, it's on to Trenitalia to buy the last leg, if you want a different departure.