Just plugging my Japanese teacher’s website: JapaneseLessonsTokyo, which was released a couple of days ago. We call him Taka-sensei.
(Actually, I developed his website. You might have noticed that the background image looks very similar to my blog’s header picture.)
I’d say Taka-sensei’s rates for one-on-one lessons are probably the best I’ve ever seen in Tokyo, and I’ve looked around a lot. If you take a 2-hour lesson with him, he charges only 5,000 yen (about $47). That comes out to 2,500 yen per hour. And he also will do lessons anywhere. Your house, a cafe, at McDonald’s, wherever is fine, and he doesn’t charge for his transportation fees or food/drinks, which most other teachers do.
So, if you live in Tokyo and are looking for a private Japanese tutor, he’s the guy to go to!