Okay, so you want to travel a lot?
One thing I would recommend is to study at a German university. You can take language courses, or courses in anything at all. Your fee for the semester is around 300 Euros (as of 2019). For that fee, half of it goes to support the student organizations at the university. The other half gets you a train ticket for your state.
Germany is divided up into several different states, kind of like the United States. You get free travel on trains, metros, and busses in that region.
But be careful! Each state has different types of trains you are allowed to travel on. I used to be able to travel on IC, RE, and S Bahns (intercity, regional, and city trains) when I lived in Hessen, Germany, in 2014.
Now, in Nordrhein-Westfalen, I can only travel on RE and S Bahns (in addition to the metros and busses). Make sure you know what type of train you are jumping on before you leave the station!
One time I was in Fulda, Germany, on my way to Marburg. I thought that my pass was good for all types of trains in Germany. It was running late, so I checked the yellow departure schedule in the station. I then ran to the next train, which was about to leave.
I got on and thought it was a very exclusive train, and was super happy to have found a seat. I sat down, out of breath, and pulled out my German language book to do a little studying.
Then, the ticket checker came around. I showed her my ticket, and she said it was not valid on these types of trains (I was on an ICE. They are the fastest trains in Germany, and do not stop at all the small towns).
She charged me 40 Euros for a ticket back to Marburg. I luckily had enough cash in my wallet. I do not know what would have happened if I didn’t!
Take advantage of the multiple options of public transportation in Germany, but make sure you get on the correct form of transportation that is included in you ticket!
“The trains always arrive at your station. The question is which one to take?” – Mehmet Murat Ildan