How to avoid big charges from 'free' apps

Web and phone apps aimed at children that charge for extras and can run up huge bills, are being investigated.

The Office Of Fair Trading are planning to ask parents about their experiences and speak to app makers to see how they market their games to you.

Some parents have been left with huge bills and there are worries that children are being unfairly pressured or encouraged to pay for stuff in free games - like upgrades, lives and things like coins, fruit and gems.

Newsround have spoken to technology blogger Tom Cheesewright about the problem. Check out the video at the top of the page.

Watch more videos