Traveling to Passau from Regensburg

Hi everyone,
I am moving to Regensburg in September to study at the university. I have a friend living in Passau who I wish to visit on a for a weekend, roughly every two weeks for the year. Can anyone recommend the cheapest form of public transport for this purpose? I need student friendly deals. I see there is a 'happy weekend' train ticket, but its only valid from 9am - 3am the next day, which isn't very useful for a weekend stay. I would be travelling alone, so the good deal group train tickets wouldn't really work either.

I appreciate any advice you guys can provide!
thanks!

Now a taxi or a bus wouldn't suffice. The train is your best option or better yet, acquire a small car (Opel Corsa, Fiat Panda etc.) and take the A3. According to Google Maps, the distance to Passau is ca. 120km.

"Acquire a small car"? What an expensive way to travel such a short distance so infrequently.

The answer to this very simple question is Bayern Ticket Single and Mitfahrgelegenheit.

Also finding groups going in the same direction as you on the train is also an option. There are frequently groups looking for a fourth or fifth person to tag on to the bayern ticket. Usually for five euros or so you can share the cost of their ticket. If you go to the machine were you buy the ticket ahead of time you will most likely find people looking for other people to travel with. If you don't find anyone, you can simply use the bayern single.

With bahn card 50 this journey coats 20,50€ return , without 41,00€ .
Bahncard 50 costs 220€ yearly , 25 journey savings @ 20,50 =512,50€ .
Plus you can use the card for other travel needs ! , a Year in Germany spent purely in Passau and Regensburg is not going to be very fulfilling .

Maybe some student can advise if a student bahncard is available !