Ah! You're so lucky to have your own craft room! All of my craft stuff hides under beds, in closets, and in my bedroom in a 7 ft bookcase. And you're organized...that's important! Unlike myself...I am always digging through stuff making a mess just to find stuff with which to make a mess.
Anyway, as far as your budget and not purchasing paint... contact your local county recycling program. Many of them have reused/recycled paint for free. You just have to go and pick it up. They come in various colors from beige to the ugliest of pinks. Check out Freecycle and Craigslist, too, to see if anyone is willing to toss out their leftover project paints and supplies.
You have a bunch of craft paint it looks like. You could also freehand some stuff as a border or something along the wall.