UPDATE: Khaosan Tokyo Ninja has closed permanently.
Khaosan has made a decent name for itself on the Asian backpacking circuit over the last few years, with no less than 11 hostels opening across Japan, seven of which you'll find in the capital. Cheap hotels in Tokyo aren't easy to come by, but Khaosan does a good line in community living, providing comfortable dormitories for both short-term and long-stay residents. The 'Ninja' location, not far from Asakusabashi Station, offers shared double rooms for just ¥3,000 per person per night – amazingly, the most expensive room on their rate card. (A dorm with ensuite bathroom costs a piddling ¥2,200.) The communal space at Khaosan is open 24 hours a day and the hostel has free internet access, free wifi, hot water showers and a kitchen with cooking and dining utensils. There's also a living room with a large-screen LCD television, DVD player, DVDs, Nintendo Wii and cable TV. Not at all bad for only a handful of notes.