I would start making a "craft drawer". We have one and I fill it with all sorts of odds and ends that I am constantly collecting - lids, string, egg cartons, yogurt containers, fabric scraps, bubble wrap, TP and paper towel rolls, buttons, stickers, etc. And I have the "usual" things like crayons, markers, glue, tape, construction paper, white paper, etc.
The girls get what they want and create from the supplies in the drawer. That's all we do for art right now.