Help: showing walls produce place look cluttered, uninviting? I'm in an apartment; the layout is stretch out; I CAN NOT...

I'm in an apartment; the layout is stretch out; I CAN NOT put any sort of hole (not even tacks) in the unclothed white walls. I'm looking for awesome ways to put LARGE, DARK/VIBRANT art on the walls (no paint allowed either!) for exceptionally, very cheap (free preferably). Really colossal posters are expensive and pretty much look like crap. Please, please donate me tips! Thanks!
Will drawing my daughter room walls oil lamp...
Answers:    You can buy those 3M hooks, you stick the one side to the wall and the other to the hook, then when you want to help yourself to it down it has a place to verbs it off, no rips, no holes, great product. It's the with the sole purpose thing I use, you can find them anywhere.