I got one each for my 10 YO and 13 YO. When I gave them the phones I made the restrictions clear to them:
- You can call anyone you want for as long as you want as long as it's on a weekend or after peek time. (It's free on the plan)
- You have 'this many minutes' of peak time to talk to your friends after school.
- You can call me anytime, anywhere, for as long as you wish.
Then you can monitor their usage online. See who they're talking to and for how long. If they surpass their limit, the phone gets turned off. It's been 6months and I haven't had an overcharge yet. There's nothing a teenage girls wants LESS than to have her phone taken away :-)