Dress suit - where to buy?

Hello,
I am currently residing in Tokyo and do not owe a suit. I will, however, be part of a delegation sponsored by Jap. government and a proper formal (business) attire is required. Thus I will have to buy a suit in the coming days.
Would you know where to get some nice suits for not too expensive? I don't want to spend more than 300-400USD. If I buy it I'd like it to last for a while.
Any suggestion, from very cheap to the more expensive suits is welcome.
As for my height - I am 6 feet 2...(thus having trouble with the length of sleeves in Japan),slim.

I've never bought from here, but this would be the inexpensive range for young people, I'd say:
http://www.uktsc.com/tsc/

They seem to have a good size range at least, you could try one on.