How much would it cost for a one week trip to Japan from the UK?

Question:

Ok so I EVERYONE (most people) want to go to Japan, but I swear I have wanted to since I was a little girl. I have been learning Japanese since I was about 10 ( I'm not really good at it, but I try =/) I'm 16 now and I think I'm ready to go. I'm going to save up, but here's the problem, I don't know how much to save up, what time of year would be cheapest to go, I really want to go to Tokyo as it is the main city with all the shops and such but I'd love to venture elsewhere if it's cheaper and just as good. Any advice? Thanks.
Oh I'm 16 by the way so where would I even be able to stay, do they have youth hostels over there?

Answer:

Heard of Google? do a search under the title "cheap tickets from London Heathrow to Tokyo Japan" choose as many price comparison sites you see and take it from there. Most airlines will not let you travel alone and staying in hotels as well might be an issue. Get written permission or get an adult to tag along