Default [Q] Disable Data on unrooted mobile


My daughter will get a s3 mini with a prepaid contract. She can use wifi at home, but she shall not use data via 3G etc because of the costs. Is there a way to disable Data almost permanently? I like to avoid that she enable it by random, and maybe she doesn't recognize.

Is there a method or an app for this? But it should be a way without root, because phone is new and I want keep guarantee.
Maybe it is no phone specific question. Where can I post it in a generell Android forum, if there is no S3mini solution?

Regards Odiad