This guide is awesome and I am pretty sorry that I did not check it out before coming as I have had to learn all of the stuff posted on the first page by trial and error.
What I will say is that you can change cash money in any bank in Tokyo. and I mean any. i have now changed up over 2k GBP in various places and have never had a problem other then the filling in of forms and taking a ticket which beats the banking in the UK.
I am rooming via Oakhouse and paying just under 70k yen per month for a private room and utils. I am here for 3 months so that is 210k yen for the period, what a bargan!
All tap water is safe unlike the toilets. If you are on a budget and want to experience the Japanese robot toilet thing then a good place is any KFC as they have the J-toilet thing for free or the cost of a burger/meal if you are worried. I am still trying to find the button that summons the maid with the butt crack brush
There are many free things to do in Tokyo and as the master of this thread says, it is the cost of a train fare to get you to a free event. The cost is minimal if you get a suica or other travel card. Plz dont get a JP pass unless you are looking to hit other cities in Japan as if you are going to just be in Tokyo the JP pass will waste your money.
Talk to the locals. I have earned much experience chatting with my local koban (police box) and they have pointed me in the right direction more often then wrong. I also have hit a few local restuants/bars and spoken to the people in the know who have pointed me in the right direction for my needs.
Do not be afraid, to resort to english, as unless you are a student of Japanese or can speak it fluently then you must resort to the international language. Japanese people will try their best to talk with you in what ever language you have, but please learn basic Japanese to clear the way for the english you are about too use. The basic please, thankyou, do you have, i am sorry, I cannot speak Japanese, yes and no should be your basic tool set.
I have been in the position of eating a bento in a park and was approached by over six people at various times offering me various foods. Many of the people sat with me and shared their food over the course of a few hours. This would never happen in London (where I am from) given that all of the people were older and their actions suggested that an offering to a stranger was a good blessing for them, I submitted too the offerings and also offered my own food to them in polite exchange that was more then not refused with a smile. I will never forget the old (I mean ancient) woman who approached me in Rikugien park and sat next to me, produced a mellon from her bag, cut a slice and offered it too me. We had had good time trying to talk to each other while munching on the mellon.
As an conclusion to my post I will add that you should not be scared or put off by anyones remarks. Just come here and understand for yourself what life is like in Tokyo.
If planned right it will not cost you much and will pay back in spades.
Again 10/10 too the creator of this thread.
Marc