you might make a rule that she shares it only with close friends and family.
Avoiding big mobile phone bills
A good first step in avoiding big bills is helping your child understand that his phone is like a wallet, and that every text message, phone call or download costs money.
Other ways that you and your child can avoid big mobile phone bills include:
discussing the cost of mobile phone use and agreeing on a monthly budget
starting with a prepaid plan. The call, text and data rates are generally more expensive than post-paid plans, but you can set a monthly limit
being aware that it can be easy to run up a large bill on a post-paid plan. This is because your child can continue to make calls, send texts and download data (at a more expensive rate) after she’s gone over the monthly allowance
discussing with your child what the consequences will be if she goes over the plan cost when using a post-paid plan
disabling MMS messages (photos and video)
alerting your child to hidden costs – for example, costs of downloading new music or apps, making in-app purchases, texting to get a new ringtone or voting on a reality TV show using SMS. You can set ground rules about not texting advertised numbers, and not purchasing or downloading content without your permission