Don't you have any money saved up in the bank or anything? I have some for a rainy day but not everyone does.
You'll have to work a couple of jobs, like someone said, maybe do babysitting for your relatives or something like that too? As for sponsors, it's usually for things like charities, not really 'pay for my trip to Japan' type stuff >.< Also, if you've got any old junk in your room or things you don't want anymore, get on Ebay and sell them off!
