My daily bus home is £1.85 for a child fare (because it's not a London bus), which I try and get cos the adult fare is double that and I'm supposed to pay that, but I can pass for 15.
Once I get to the edge of London the buses are free and I can travel to anywhere in the city for 50p (or £1 if I have to use the DLR on the other side of the city). Student Oyster card <3.