Oden was originally what is now commonly called misodengaku or simply dengaku; konnyaku or tofu was boiled and one ate them with miso. Later, instead of using miso, ingredients were cooked in dashi and oden became popular.
Unlike most one pot dishes, ingredients can be added at any time. Oden is often sold from food carts, and most Japanese convenience stores have simmering oden pots in winter. Many different kinds of oden are sold, with single-ingredient varieties as cheap as 50 yen.

It's never occurred to my how easy it is to make your own oden!! Man... thinking of all the money spent buying Oden from so many convenient stores and school's cafeteria, I think I can survive making the homemade oden for the whole month! Dang it! (yum~~ :9)