I was amused by this “Little Buddy” device that Best Buy sells. It’s a GPS unit that your child is supposed to carry around so that you will always know where they are.
I can see this being a good thing for children of high profile people, where kidnapping might be a possibility. But normal people? My advice is to communicate with your child. Ideally you have a trusting relationship with them — they tell you where they are and when they expect to return. A pay-as-you-go mobile phone would allow them to communicate with you in a situation where they need to make a new plan. And that would cost less than the $15 a month that the Insignia plan requires (if your agreement with your kid is that you will pay for those kinds of calls or texts only).
Finally, I admit that we are of course not perfect parents. And also, some kids just make bad choices. I don’t think those kind of kids would readily carry around a “Little Buddy” in their pocket or backpack. Chances are, they’d leave it at their friends house before they went off wherever it was they wanted to go.