It's easy to make your own non-toxic finger paints at home.
You will need:
225g corn flour
250ml boiling water
To make the paint:
1. Mix the cornflour with 100 ml of boiling water.
2. Stir together, adding the remaining water a little at a time. The cornflour resists mixing with the water to begin with and needs coaxing. Consistency is a matter of choice - thinner is best for using with brushes. Thicker is better for using fingers.
3. Add the food colouring and mix well (if making more than one colour, divide the mixture first.)
The paint may last a few days in the fridge but, like any food, goes off eventually.