Not much of a great deal but if you are topping up on O2 this month they are giving Gold rewards to everyone for a 10£ top up. You get a code to enter each time you top up.
'' One month of scorching hot surprises
Normally if you top up less than £15, you can only win one of our Silver Surprises. But from the 3rd August to the 31st August, you're instantly able to get a Gold Surprise every time you play.''http://topupsurprises.o2.co.uk/