/diy/ - Do It Yourself

I'm sitting in a room that's almost empty. I have a table, a bed and a wardrobe. My cousin stays in the room and the wall separating them is thin. I need to soundproof my room, every noise sounds so loud. If I drop a coin, the whole house will hear it, I can't do shit without anyone knowing. I was thinking about using some suction cups and hanging some sheets/towels on the walls.
What do you think about it? Do you have any advice? (My budget is...10$)
Also, I don't know where to look for the suction cups, I need some suction cups with some holes, so I can tie some string to them.