Seeki.eu lists 25+ properties for sale and 5+ to rent in Grünheide (Mark).
The median asking price is €430,000, or €3,213 per m² on a typical 130 m², across sale listings that publish both a price and a floor area.
On the rental side, the median asking rent for an apartment is €1,250 a month, across apartment rentals that publish both a price and a floor area.