Up-to-date Transport for London (bus, underground & train) prices can be found here:
How to get from my Airport to my accommodation/ English school in London
Get your visitor Oyster travelcard delivered to your house in your country!
A typical takeaway lunch in Islington will cost around £8 including a main course, a drink and something sweet for desert.
Black London Taxis are very expensive.
The bus is usually the most economical way of getting to school.
If you are driving, then watch out for the congestion charge!