When I am just wanting to let loose with my art, I turn to cardboard. It's readily available and I feel open and unintimidated in fear to "mess it up".
I used acrylic paint, black stabilo marks all pencil, and cray pas oil pastels.
They are now listed in my big cartel shop! don't forget to add code CHRISTMAS15 to save 15% now to the end of the year.