Make your own sidewalk chalk for kids, and save a lot of money compared to buying it in the store. And you get let your kids pick and choose the colors.
2 c water
2 c Plaster of Paris
2 tbsp Tempera Paint (Wet or Dry)
Toilet Paper Tubes with duct tape, taped tin foil, etc, or any other similarly sized container.
Combine all ingredients and stir together, then let stand a few minutes. Line a cookie sheet with wax paper or tin foil, then place your tubed containers on it. Pour sidewalk chalk mixture into holders, let stand until somewhat firm. Then remove the tubes and let dry completely (about 1-1/2 – 2 hours. Throw out any leftover chalk mixture (WARNING: do not rinse down the sink).