I have tried the Bake it clay with kids. It's rather musshy.
Same thing with Pluffy . Clay separates instead of staying together when conditionning. Dries fast too .
The kids and I did not like both of them. Not many colours for one thing and the musshyness with kids who have very hot hands is not a good beginning for them. Both clay perfect for filler perfect though.
Earaser clay is another clay that I don't like with kids. It doesn't earase properly.
Sculpey III seems better for kids. They only thing it's not good to make sculptures with tiny things that stick out or to make thin plaques. Every small thing breaks too easily even when well cured.
If you want to do things to sell stay away from Sculpey III or the Michaels brand or mix them up with the harder clay like premo, kato, cernit or fimo.
Rule of thumb: you get what you pay for!