If you are placed at a university, you may be offered a local transportation pass as part of registration fees. Always check with the International Office.
Flixbus is the largest long-distrance provider, but there are also options from IC Bus, among others. Many buses are new, have wifi and tickets can cost as little as €5.
Don't be caught without a ticket on public transportation! "Schwarzfahren" - riding without a ticket - can result in large fines and public shaming.
Carpooling company BlaBlaCar is a favorite amongst Europeans. You can also check out mitfahren.de to explore both car share and bus routes.
