How do I decorate my room without using paint?
We just moved in to an apartment and the building administrator told me that I can’t paint the walls black or red. If I want to, I can use paintable wallpaper and paint over it. But then, it’ll be twice the cost and work to actually paint my room that way. What are some things I can decorate my room with without using paint? Preferably black and red design.

You can buy inexpensive fabric in red or black or a combination pattern (in the back of JoAnn fabrics in the $ .99 to1.99 bolts). Attach it to the wall using liquid starch. Simply soak the fabric in the starch using a wallpaper tray, smooth the fabric on the wall and use a credit card or putty spatula to remove the bubbles. Overlap the pieces of fabric for finished looking seams. I allow my rental tenants to use this techniques on their walls because it does not damage the walls and can be lifted right off the wall when they leave.
wallpaper
Decorative stickers
fashionable in Europe right now, guess you might find them.