Got an Answer?
You can get it for free from your vagina!
If you cant find it, and cbf buying it and paying for postage, you can always look up recipies for said slime online and make it yourself.
I once saw a recipe someone had made for cloud dough, and seemed pretty simple. Anyone who made it and gave feedback seeed to rave about it's popularity with their kids.
Also, sometimes making such stuff yourself is half the fun.
Just try it.