Have just been with my grandsons and their friend has been found to have had 500 pound scam done on him via iphone.A smurf game was offered to him free on the iphone and it then asked if he wanted to carry on. The subsequent games have cost 500 pounds. You can buy cards which seem to be a safer option.
This was mentioned on Watchdog and I believe people were able to get their money back but I never saw the programme myself.