First, be warned: Japan is very weird. I have family there, and every time I hear from them it turns my hair a little whiter. The Japanese have big huge sticks up their collective asses about things like success, social position and reputation. But if you can tolerate the workaholic Victorian atmosphere, here's what the smart guys do when they go to Japan:

Step one: Bring many pairs of jeans, the more rough-looking and worn the better.

Step two: Sell said jeans in the streets. This is not hard; genuine American jeans are a big fashion statement that the rebellious youth of Japan use to piss off their parents. Depending on your jeans and where you are, you can sell them for as much as $200 (remember to convert to yen) a shot.

Step three: Use jean-money to buy anime, which goes for the equivalent of five to fifteen bucks a video.

Step four: Sell said anime back in the states for $30-$50 a video as what it is--a genuine import.

Well, that's the official instructions, but I would add two things here:
1. You might want to research the specifics about the street value of your jeans in the area you're going to, and also the U.S. resale value of the anime you get, and
2. For god's sake, keep some of that anime for yourself--or better yet, give it to me.