This is probably the most cheapest way to decorate a whole room I’ve ever seen. Even though it seems more like a temporary solution it still can be used as the permanent one that you can easily renew any time you want. The cool thing is that your decor won’t occupy any space so it’s perfect for small rooms.
On the pictures you can see such decor. Almost everything in this bedroom, including such things as a headboard, a table with a vase, a wall clock, a floor lamp, is cut out of ordinary cardboard boxes. Details are painted with ordinary markers. All these furniture silhouettes are mounted using double side tape.