Stopover trick when buying tickets on Bahn.de
 

As I and others have pointed out, it is often possible to buy cheap tickets on Bahn.de, both within Germany and to/from other countries. These tickets can be obtained for as little as 29 Euros or 39 Euros, if you buy while supplies last, starting approximately 3 months in advance.

I was lucky to be able to buy a 39-Euro ticket for November 18, even though I had postponed purchase until today. This leaves Munich in the evening of November 18, and goes to Passau. I chose the option to have a 16-hour stopover (it actually ends up being a little more) in Passau, and then the following late afternoon I head to Vienna. I did this by using the Via option and choosing a stopover time, on the search form.

If I bought the two tickets (Munich-Passau and Passau-Vienna) separately, it would have been more expensive. So far as I could tell, I could not have done this, for my dates and times, for less than about 72 Euros.

Great info. Thanks for sharing. I'll have to file this info somewhere in my brain for future travels!