Students from non-EU countries must apply for a visa for entering Germany in most cases. Please note: A tourist visa cannot be changed to a student visa afterwards! For more information on the visa application and regulations please check the website of the German Academic Exchange Service (DAAD)
After your arrival in Weimar, you should register your address with the city authorities ("Bürgerbüro") as soon as possible. If you are a non-EU citizen, you must apply for a residence permit at the immigration office ("Ausländerbehörde").
In Germany you can pay almost everything in cash or by debit card. For regular transactions such as paying your rent, health insurance or for transferring the semester fee, you should open a German bank account.