Some of my favorite dishes from my time there include:
"Okonomiyaka": /w mayo and that brown viscous sauce I can't remember the name of. Cheap and filling, it's also easy to make.
"Kaire Raisu": Mmm... yummy! I am particularly fond of "Seafudo Aji ka Katsu Kare" (Seafood flavor or "Katsu"-a breaded cutlet) variety. Coco's Kare House with the big yellow huts serve up a mean Kare with a nice sized portion and relatively affordable as well.
"Genghis Khan": A
Hokkaido specialty if memory serves, similar to what is also knows as "Mongolian Barbecue" or "Viking Buffet" where you are charged by the hour and grill your own meats, vegetables, seafood, etc. Can be a bit pricey but if you're eating out and want to impress your friends visiting Japan for the first time, there is no better deal. Sapporo Beer Hall, 'nuff said
Sunkus, Lawson, Seico Mart, 7-11 "fast food": Hey gimme a break, I couldn't afford to eat out all the time, and I swear those Oni Giri sure hit the spot in a pinch when I didn't feel like cooking 8-p
"Mos Burger Hotdog": The closest thing I ever found to a good 'ol American hotdog lol.
"Takoyaki": An acquired taste but cheap and filling.
"Gyouza": Ahh, Gyouza... days gone by...
"Kare Udon": If you like a little spice with your udon, this will hit the spot.
"Sushi": An absoulte must-have. Certainly an acquired taste for some, but when you've got that craving, it's hard to squash... Personal favs include Benisake and the classic Maguro (Salmon and Tuna) varieties, although I like most types.
These are just some of my favorite dishes that I found to be affordable and delicious and most could probably be labeled as "fast food" lol. Certainly, one could always drop a few Yen at a Bikkuri Donkey or Victoria's Steakhouse but I preferred the simpler dishes. Unfortunately, here in Grand Rapids, MI trying to find a good variety of quality affordable ingredients to make one's own dishes at home is very difficult. And trying to find fresh seafood here, is well... no comment 8-p