Or... buy some canvases ( generally square looks better), from the $2 shop, and use any paint you have lying around the house, particularly tester pots, which are similar hues, and try your hand at making some yourself!!
Just pour the paint on, tip the canvas side to side a bit, do a bit of mixing with your fingers and 'Bob's your uncle".
I have done this a few times, and they've come out looking pretty good!!
If you want to start getting fancy, you can first put on some glue in wavy lines, let it dry, and then do the colours over the top, to give it some texture as well.
Even if it doesn't work out well, painting is very therapeutic!! particularly finger painting!!
Pen