.50 pack of Crayola crayons are random colors left from the bigger packs. Most do not have the primary colors in them so check before buying.
I bought several packs of the school price Crayons. There were variations of colors but no true basic colors like black, red, blue or green. Maybe one box in ten had a basic color. Buy the regular priced box and some of the others as filler colors. The best crayons to use are the Crayola crayons made for construction paper. They are vivid and jewel like colors. The kids can tell the difference.