Come London and hang around UNIQLO. You're bound to run into Japanese students. =P
Although I do not speak Japanese nor can comprehend learning it (for the time being) I would say your main concern would be to prioritise yourself.
Do some little learning and a lot of working, save up the money! If you want to experience Japan then you best visit it.
Nothing can prepare you for a different culture, the only way is to live it!
Estimate dosh needed to have a fab time would be around 3 grand, =O
Those Nigerian emails are cool. "I have a diamond mine and I need a supervisor, but would you like a bigger penis!?"