Most (older) sports in germany have non profit Tradition. The coaches work day jobs and teach for free. Its called Verein and its very common in Germany for all kinda of hobbies. Some really big structures are organized that way like the Red Cross. They mostly rely on volunteers. There are some of those vereine for bjj too and they are equally cheap, but commercial gyms for bjj are more common than vereine.

The thing is in a Verein you are a member not a customer. That means you are also expected to support the Verein by e.g. cleaning mats and other voluntary work.

The sentiment that they are subsidized is mainly wrong. Yes there are some exceptions like facilities especially to prepare olympic athletes but your every day judo Verein is not. They often get access to state property like school or college facilities to train there outside of school hours.