For a truly mess-free art kit, i.e., no dried-up Play-Doh crumbs, papers lying around from peeled-off stickers, and zero risk of stains, you can’t do better than a Crayola Color Wonder set.
SAVE 25%: The Crayola ... your paint pouring journey. You'll get 10 two-ounce bottles of non-toxic, washable acrylic paints. So when you inevitably make a mess on your first go, it's no biggie.