Blend 3 Tbs each: cornstarch, baking soda and white vinegar and 1 1/2 tsp light corn syrup.
Blend well then divide into containers and add food coloring.
Allow to set up 24 hours. You may need to stir paints while using as sometimes the coloring separates from the base.
We bought small salad dressing containers at Dollar Tree. They hold about 1/4 cup, and have a lid. Perfect :)
You could use any small containers...the recipes I've seen online use little dixie cups cut down shorter, and even the tins leftover after your tea lights burn down. I'm using these because I have 8 children using these paints and wanted a bit more per color.