Favorites
I've found that doing art with my kids is one of the best ways I can connect with them.
Since they were babies, we've pulled out supplies to sit and create together. As they're getting older, it's usually only once their hands are busy that they start to open up and talk about what's on their hearts and minds. These are some of my most favorite (and low-mess) supplies, all under $15.
*Every item here is one I have used and loved with my own kids. I will receive an Amazon Affiliate fee if you purchase through one of these links; as a small business I only choose things I stand behind and appreciate your support so much always!)
Magic Clay Kit
$6.99 for 24 colors and tools
I love that this set comes with so many color options, and basic tools. My kids love the squish-ier texture of this clay, and it's less messy than playdoh since it won't crumb. I set them up on trays and let them pick colors to open. This clay air dries to permanent in a few hours, so we keep it bagged up tight when we're not using. Great to bring with you on trips or for stuck-inside days! 
Washable Markers
$12.97 for 65 colors AND a carrying case
We love this line of markers, and the smaller size means easier for tiny hands PLUS you get double the color options. The carrying case is great for travel. My kids love to "marker paint" with these, a cup of water, and a paintbrush. You can draw lines or shapes onto regular paper, then brush over them with a little water for a watercolor-style effect. Very low-mess since everything is washable... or just water! 
Great Basic Paintbrushes
$3.99 for 10 brushes
I use these brushes myself with acrylic paints, and set up a cup for my kids of ones they can use, too. They last and wash really well.
Spiral Sketchbook
$5.99 for 2 sketchbooks
I keep a notebook for each kid in my bag at all times. They love to decorate their cover, and we pull them out on the go when we're at a restaurant, waiting in lines, or just want to sketch something to remember. We play tic tac toe, write little funny ideas or memories, or just draw away. Kids love having access to this type of book so I really think you can't have too many. 
Colored Pencil Set
$8.99 for 72 pencils and set
Colored pencils are one of my favorite mess-free kid art supplies! I love a set that comes with a carrying case, or you can use a recycled jar to store them. I throw these in a zipper bag when we travel since there's no caps to lose or drying out to worry about. I love the range of colors and can also sketch ideas with them myself!
Collage Kits (everything under $6!)
We have a shelf where my kids can easily grab their own choice of colored paper, safe scissors, and glue sticks. It's taken some practice for them to use things and then put them away, but they love the independence of being able to easily create. I love seeing the collages they come up with! This is truly a shelf of endless possibilities.
