Wax pencils: I assume you are wanting these for chore charts. They are also known as "grease pencils" and you can easily find them online for under a dollar. I think a art supply store would have them too. I see the butcher use them to write on that white, waxy meat-wrapping paper. You might ask them if you can buy a few from them. I have used wipe-off crayons and also washable markers for my chore charts and they work fine too.

Thanks for writing!