As LocalHorst can not exists out of nothing we need an organizational background to give a needed structure for legal and financial topics.
The most realistic approach would be forming a club as "Gemeinnütziger Verein / e.V.".
To do so we need to set up a constitution compatible with the recommendations of the state NRW. The so called Mustersatzung.
After forming a e.V. all expenses, financial questions, contracts and stuff should be taken over by the e.V.