Orange calls to landlines dolphin pay monthly?

I recently got a HTC wildfire s phone as my other one broke. I get unlimited texts, free internet and 100minutes calls. I did phone up for competitions and there were 0845 numbers which are not free which I found out but are 0207 numbers free as it is a London phone number and it is British. I just don't want to get paid alot on top of my 15 pound a month. Thanks nicola