Is it expensive to snowboard in Japan?

Yes but not everything. Currently the yen is very strong against the U.S. dollar as well as other currencies. That means your dollar doesn't go as far. Lodging can also be expensive.

Lift tickets, on the other hand, are fairly cheap, running about $50 - $60 per day U.S. Food can be either expensive or cheap, depending upon what and where you eat. Food at resorts is, like everywhere else, a bit expensive.

Transportation costs can be checked online. They seem reasonable to me but definitely not cheap. For info on trains, check out http://www.hyperdia.com/en/.

A good website to learn about resorts and hotel options is http://www.snowjapan.com/e/index.php.

This should get anyone started.