A Dutch startup called Add My Window is allowing city dwellers to rent out their public facing windows to companies looking for alternative ad space. Advertisements come in the form of large stickers that get placed inside the window. The stickers provide vivid image outside but still allow some light to pass through because they contain hundreds of small holes.
Sure, you'll tick off your neighbors or your landlord with these advertisements. But if you're having trouble with the rent or mortgage, Add My Window will pay you up to 150 Euros every month to turn your public facing window into a billboard. Not a bad way to make make money, huh?