hey wuzzup yall..
Prices in japan can range from ass rape to not so bad. As for importing, the Japanese Gvmt dont give a shit. You can check the Narita Airport customs page for a list of restricted and prohibited items. Also, on the Ministry of health, they allow you to import a personal supply w/o any problems. The Japanese gvmt just doesn't want you selling shit on the streets.
If you decide to import, your package will (most likely) be opened by customs and they will investigate what it is. If you can track your package, then call whoever your courier is and ask the status of your package. They'll probably give you a number to Tokyo Air Service or Customs and you'll have to talk to them.
My advice: they'll probably ask you what it is, just say bodybuilding supplements. If they inquire further, say its your muscles. If they ask what kind of drug it is, say you forget. If you can speak Japanese or have a Japanese friend, then that can make things easier. Remember, you don't want to sound like you're a dealer moving big stacks of roids and selling them on the streets of Shinjuku. That's pretty much it, they don't really give a shit.
peace