When you homeschooling your children it is always important to find great affordable materials. It is also great to find learning materials to supplement public-school holidays and vacations. Here is a great product that I have found incredibly useful in teaching our four-year old.
These are markers that do not dry easily (even when left out open for days, been there) They are easy to hold and manage for little hands. We use them for school work like:
You can find them at: http://dotart.com/
They are also sold on Amazon, EBay, and some nice toy stores.