You can find one of the best Chadougu shops in Shinjuku district.
The shop is called Seishoen 青松園. They are open everyday, except national holidays, from 10:00 to 19:00. Their telephone number is: 03-3342-6007 (if you're calling from an international line +81-3-3342-6007).
It is located in the Shinjuku Odakyu department store, from West Exit of Shinjuku station. Once you leave the station from the west exit, look for the BicCamera sign on the Odakyu west department store building. You will find the chadougu shop to the left of the BicCamera entrance.
They have a lot of items and with a big range of prices.