Is it better to purchase tickets before you leave, say from RAIL EUROPE or wait till we get there. We will be traveling from Vienna to Innsbruck in first class and later from Oberammagau to Munich
First of all, Rail Europe and similar agencies sell tickets at a mark-up, so they are rarely, if ever, the best ticket source.
Deutsche Bahn (German rail) offers some advanced purchase discounts, but usually for longer distance trains. For a relatively short regional rail trip like from Oberammergau to Munich, I doubt they sell advanced discounts (but Lee, the German rail guru of these forums, will correct me if I am wrong). Just buy your ticket on the day of travel.
I don't know if Austrian rail sells advanced discounts... if they did, I imagine one would be available for Vienna to Innsbruck.
I agree that there is no reason to ride in 1st class in trains of German Rail. If you insist on 1st class, a ticket from Oberammergau to Munich is €27,40 per person. That only covers Oberammergau to Munich Hbf.
If you can bring yourself down to ride 2nd class with the rest of us, you can purchase a Bayern-Ticket at the ticket automat in Oberammeragau for €28. That will cover up to 5 people on the regional trains from Oberammergau to Murnau and on to Munich. Regional trains are pretty much the only trains from Oberammergau to Munich anyway. It will also cover the bus to Murnau and the train to Munich, if you want to go that way. The Bayern-Ticket is valid after 9 AM workdays and all day on weekend days. It is valid until 3 AM the next morning.
The Bayern-Ticket is also valid on all conveyances (U-/S-Bahn, trams, and buses in the Munich metro distric (MVV) for the rest of the day once you get to Munich.
Although you can purchase regional tickets, such as from Oberammergau to Munich online from the Bahn, there is really no advantage; the prices are the same from an automat or counter, the tickets never sell out, and there are no reserved seats.
Wait until you get there. We visited 8 countries in 8 weeks and would purchase our out going tickets when we arrived in a city. We had NO problems.
Thanks to all who replied.