I've been asked a few times to show what Japanese grocery stores look like, so here's my attempt to fill those request. Unfortunately I went a bit late, 8 PM, and a lot of the sections of the store were being packed up, despite it being a 24 hour grocery store. So I couldn't take proper pictures of the pre-packaged foods, bakers, fish and meat sections. But they are very similar to those seen in western supermarkets.
All these pictures were taken at a mid-range super market, not the cheapest, not the most expensive, so prices should reflect what is relatively average here in Japan.
Seeing foreign beer in Japanese grocery stores is pretty rare. If you ever do see any, they are usually Budweiser, Guiness, Heineken and Corona together, that being because Kirin handles the distribution of all 4.
Japanese beer comes in very few styles, almost all being of the "Japanese Rice Lager" variety, even if its branded differently. The heavyweights here are Asahi, Kirin (who are always back and forth as the #1 beer) and Sapporo. Light beer does not exist at all in Japan. The cheap beer, Happoshu (around ¥98) is technically not beer, but rather an "off beer" being that is has less than 67% malt content. It's marketed pretty similar to how Bud Light is in the United States.
Also, while you can buy 6 packs, 12 packs, etc here, you don't buy them at a discount. You'd be paying the exact same amount as you would if you bought the cans individually. The same goes for virtually any product in Japan.
Unlike in the U.S. there are no laws limiting the size that commercial alcohol can be. Not pictured is a 2L of Asahi beer. These are typically intended to be used at parties or picnics. I know that most western college campus' would be much worse of if these existed in their neck of the woods.
As you can probably tell, fruit is pretty pricey in Japan, especially now that it's out of season. However, vegetables are moderately priced. In order to not spend ridiculous amounts of money on food, I've stayed away from foods I'd typically buy back home and eat as the Japanese do: Noodles (udon, soba, yakisoba, spaghetti), rice, vegetables and such.