I know a person who started using an app called Recolor that was free for the first month. But after that month was over, a monthly subscription fee of 7.99 was charged each month to my credit card.
The best site I found that helped me delete this absurdity was found at this link
https://appletoolbox.com/2012/11/how-to-cancel-automatic-billing-auto-renewing-subscriptions/
I hope this helps any parents out there who wasted their money on an app when their child was tricked by the "free" trial period. Good luck!