Proof you don't need to shell out a small fortune to eat well in Tokyo is this humble restaurant specialising in Sanuki-udon, wheat noodles from Kagawa in Shikoku. Pay at the vending machine; you'll be handed an English menu to help with the options, which include the amount of noodles you wish and the toppings. The curry noodles are excellent.
Kagawa Ippuku
Kōrakuen & Akihabara