Honestly, even in joint family one shouldn’t have problem decorating their room. If painting is a problem, one can always keep the existing paint, and play around with other things in the room. One can always buy a nice bed set, some acessories to with, move around the furniture in the room and there you go. One really doesn’t need a big budget, it can be done in/with a small amount of money. You don’t need anyone’s permission on how to decorate your room, the room you are living in.