[Hatix]

Well, since you're flying from the US, it's a bigger distance than from Belgium (where I'm coming from) to Tokyo. But I'd say that price is quite normal. Also, don't type in Yokohama, search Tokyo, Yokohama doesn't have an airport, and you'll be going through Narita anyway.
Also another tip for flights, try to wait a bit with the flight, there are always some weeks where the prices drop significantly but as this is unpredictable it might not be of help to you. My experience tells that between 2-3 months before departure you have such a week. I've gone twice to Tokyo before and had it both times. I even waited too long and missed a very cheap flight, and ended up paying 100$ more, and while it was still cheap, it was a missed oportunity. I can give you the prices but you cannot compare them because your distance to Tokyo is bigger.

Then, about your hotel, that's quite an expensive hotel there :p. Since you entered Yokohama as destination you got a hotel in Yokohama, but that's not really necessary. You better take a cheaper one in Tokyo, and then take the train to Yokohama, that's easier (and cheaper). I recommend hostels, they are quite cheap being around $50/night, and probably less if you're going with another person, and they are actually just like other hotels. Try looking for Oak Hotel or Sakura Hotel or look on hostelworld.com. I think you should be able to book only a flight on expedia, no?

Lastly about ticket prices, you have 2 options: buy them up front or buy them in the reseller stores. Buy them up front by using auctions on Yahoo Auctions Japan. Tickets can range from (indeed) 600$, to 50$, depending on their location in the arena. Those 600$ ones are really front front A-block row. Stay away from those ;p. Try non-front rows or Block B (which is still very good), and you can get prices from 100-300. But since they're auctions, prices can vary and can get bigger. And since they don't send them internationally, you'd have to use a 3rd party and that also comes with a cost. But, this way, you end up stepping on the plane with your concert ticket. While the second (and mostly a bit cheaper) option is to buy in the reseller shops. The closer to the concert date, the cheaper the tickets become, but also the smaller the availability.
Last year I went to 2 concerts in Yokohama, for the first date I bought them in advance, but quite expensive but B-block seats, and the second date I bought them at a reseller shop. Locations of reseller shops and arena layouts & block numbers you'll find throughout this thread, but I think it's still a bit early to buy them, wait until next month at least.


Just my 4cents ;p