Finally got pushed to make an account to reply to this. I visited Japan (almost exclusively Tokyo) for almost all of April in 2010. It was my first time out of the country, and I had only a SLIGHT passing knowledge of the language. The round-trip ticket (about three months in advance, flying from New Mexico) set me back about $1700. The full trip total cost me about $5,000, but let me elaborate a few things you should know that will save you money.
First, if possible, find a friend who can make the trip as well. My half for the hotel I was staying at (in Shinagawa, three weeks originally) only cost me around $250, split with my friend. For transportation, the first thing you want to do is buy a rail line card. It saves so much time and confusion- you put money on the card and scan it every time you use the subway (which you'll be using alot). You don't even have to take it out of your wallet- I would just sit my ass on the scanner and would be good to go haha.
As for the language, you don't have too worry TOO much inside of Tokyo. While there wasn't nearly as many people who spoke english as I thought there would be, the two of us got by just fine. Your best bet is to snag an english subway map and hit a few areas where you're bound to find some english speakers, and make some friends. Shibuya, Shinagawa, and Roppongi (especially), are your best bets.
For things to avoid...... I'm not sure how much you like the club scene (which is AWESOME in Tokyo), but there are a few ways to avoid spending as much money as I did. One: if you're going to the club (I can tell you how to get to some awesome english-speaking ones) pre-game beforhand. Alcohol in the club is EXTREMELY expensive (unless its happy hour, or "happy day," in which case expect it to be packed wall to wall). I was paying 900 yen for one bottle of Budweiser, wich at the time was about $11. Two: never...... NEVER trust Nigerians. For some reason there are a ton of them in Tokyo, and their whole purpose is to prey on forieners (or gaijin, as you'll learn). They'll offer you what seem like amazing deals, like all you can drink for 1500 yen an hour (less than $20), but don't fall for it. Make some japanese friends and you'll avoid this problem altogether.
All in all, after you've made a few friends who can show you the ropes, don't be afriad to drop money on a new experience. Plan it out a decent time ahead, and make sure to bring more money than you'd ever DREAM of spending. Even if you don't spend it all, you'll always have a fallback. Hell, if I could save up enough in time I'd make the trip again this year too. That month I spent there was the time of my life, and I wish you the best when you get there. Let me know if you have any questions, or want some more advice.
