A question that comes up occasionally on this site refers to using the Dauer-Spezial-Tickets in Germany. On my last trip I used them twice.
I purchased the Dauer-Spezial-Tickets online from the German Rail website, where they are listed under "Savings Fares". Tickets must be ordered three days in advance, which was no problem since I ordered them from the states before I left. It is a good idea to order them as soon as you can commit, because the price goes up as the lower priced tickets are sold. Tickets are non-refundable, so you should not order them before you can commit.
The tickets were from Cochem to Bad Harzburg (via Köln and Hannover) and from Walkenried to Karlsruhe via Northeim, about 625 miles total. Each day included at least one leg on a long distance (Vernverkehr) train (ICE/IC/EC), as required for the Dauer-Spezial fare, but also included at least one leg on regional trains to get to/from a smaller town. The full fare for both trips would have totaled €175. Dauer-Spezial fares start at €29 per trip; that is what I paid.
I ordered the tickets online, paying with my credit card. They sent me a .pdf file to print out. I did so on my home printer using standard letter sized (8½ x 11) paper using "no scaling". When I got to Germany I asked my first host to print out the ticket on European sized paper. The "bar code" was a slightly different size and shape, but the conductor scanned my (Amer. paper size) bar code without a problem.