Just buy a cheap one. My son has one and it entertained by it, but the only thing you can really do is flatten it and watch it pop back up. But he finds it very entertaining. You might want to make sure the girl knows that they do not do much else.

The little girl (turning 7) I nanny for has asked for this Phlat Ball (I'd never heard of it) for her birthday, and I really want to grant her wish, but it has such bad reviews!! Does anyone have experience with one of these or could recommend a certain version (there are many)? Or a similar toy? Do I just get it for her anyway even though it sucks, or get her something different?

Thank you