in je ogen waait de wind
it happened to another friend of mine actually who had to go 30 days as well and did decide to go but he changed his mind after two days inside (did save him 60 euro).
prisons in berlin are full of people who have been caught dodging fares in public transport and weren't able to pay their fines. it is obscene yes, and not that it should matter, but even from an economical standpoint it doesn't make sense, incarcerating these people actually costs more.30 days of jail over 1000 euro? What is this possibly for? What a silly, obscene system, to lock people up over 1000 euros