Cheapest Tokyo lodging

I will be going to Japan next year and I plan on staying for at least three weeks. I have dreamt of this trip for so long and I intend to see, learn and experience everything I ever wanted related to Japanese culture. I know that it is not a cheap town at all, but I will be looking for some cheap lodging there. Can you help?

Phew, Japan really is expensive, at least for me. I have been in Tokyo last year and I have to admit that even though I thought I brought enough money, it was far from that. But I did make a mistake and went into four star rated hotel and I cannot even say how much I paid for it. Later, I found out for some much cheaper places, so I can recommend Ginza Hotel Rafiinato (price for room goes from 7200 yen per night).