How much would it cost to go to London, UK?

Where from? For me it's £4, because I live about five miles away. For you, it might be a bit more, because you might live a bit futher away...

It would not cost me anything I live in the middle of London, the question should be how much do I need to survive in London as London is now overtaking Tokyo as the most expensive city on earth

There is only one way to answer this question............. Find out from the airlines , travel agents or internet. No one can tell you here.

Where from? New York? Sydney, Vladivostok? Silly question really.

I am assuming you are in America--flights will cost between $700 to $1200. Depends on where you fly from and when you go. You will need around $800 to $1000 for 5 days hotel stay (as you will lose nearly 1/2 the value of the dollar when you exchange for pounds) look at some of the accommodation (hotels & B&B) websites for an idea of rates. and figure at least another $1000 for shopping and eating, travel. More if you like to be extravagant and buy a lot of stuff.

You can get a round trip ticket for about $700, but depending on how long you are going to stay there will effect the cost. A week long stay will run you about 2000US including flight. But it really depends on what you plan to see, where you stay, and if you're going to Harrods.