You will never buy store egg dye kits again! I promise. 
This is so simple it’s crazy! And you most likely already have the needed ingredients at home in your kitchen.
What you’ll need-
Vinegar
Water
Food Coloring
and hard boiled eggs of course! 
Add 1 tsp. vinegar to 1/2 cup of boiling water. You will need at least 25 drops of the color of your choice and depending on how dark you want the color will depend on how many more or less drops of food coloring you’ll need. Dip the hard boiled eggs in colored water. The longer they sit in the water the deeper the color. The kids like to double dip (the only time it’s allowed when sharing in our house!) haha… and it makes for some pretty Easter eggs!
I've used a similar recipe for years with my children and now too with our grand-kids, they turned out lovely.
It's nice knowing you already have the things you need in your kitchen cupboard to do this and not having to worry about fighting the crowd in the stores to get an eggs dying kit!