Cheap Slime Ingredients or Powders?

My kids are into making slime and recently bought a set which had sachets of powder that you add water to to make slime.

The set was quite expensive as it had other stuff in.

I’d just like to buy some cheap slime powder if it exists but can’t seem to see any low priced stuff?

Has anyone seen any? Or cheap versions of the ingredients people make slime out of?

Seems like the kits are marked up a lot, when it looks like all you need is the powder?

Thanks