K.A.
They don't have to be the prang brand, it's just like crayola it's just a name most people are familiar with. More then likely what is going to happen is the paints, crayons, pencils, etc will go into a community pile and it is all shared, or at least when my kids were in the lower grades that's how it worked. I'd not worry about trying to find that brand name and just buy what you can find.