Cost of living

Could anyone please give me some idea about the cost of living in the London area?  for example, how would you consider a salary of 45,000£/year? low? average? good?  Besides, how much does taxation amount to in England? 

Maria, we invented taxation. We're very good at it too, because if you work for someone you have to pay tax on the wages that you earn. Then, every single thing you buy is taxed, so you pay out again, with the wages you have left after tax. Then there is National insurance contributions, invented a long time ago to fund the NHS, difference being it worked then. Then you have VAT on all your purchases. If you drive a car, you have to pay road tax, if you own a house you have to pay council tax (the amount varies from area to area, depending on their greed.) If you are lucky enough to have any money left after all this, don't save it with the bank or building society.....you guessed it, it will be taxed. Going back to your earlier point, £45,000 in London? You will have to live outside the city and commute, sorry.