There are some definite caveats. While you're not about to run into overage fees thanks to an on-by-default Safety Mode (which allows unlimited low-speed data once the 5GB runs out), your child will be stuck with 480p video streaming. Other perks like tethered data aren't included, either. On top of this, you can't get away with a low-cost subscription for yourself -- at least one line has to use an Unlimited plan.

The big question, of course, revolves around whether or not it's worthwhile if you're a concerned parent. That's not so clear cut. Carriers like T-Mobile and Sprint drop the per-line price to as little as $30 for four people, all the while preserving unlimited on-device data. You could use the savings to get third-party parental control software that isn't tied to a specific network. Just Kids makes the most sense if you expect to stick with Verizon and prefer the simplicity of a bundled parental control subscription. Otherwise, it might be best to shop around.