The Japanese "Dagashi-ya". It was never intended to be a shop selling an authentic Japanese snack experience (Wagashi has that covered), but as the years go by it is in some ways a type of shop that time forgot.

Anecdotally, I think many dagashi-ya are staffed by the elderly, and the outlook for their existence in fifty years time is something I wouldn't put much confidence in, but first, what is "Dagashi?"

Most simply it is very low-cost candy sold individually, so that you can find yourself paying from 5 to 35 yen. This lets you buy a wide variety of things you'd like to try, and you can make a really large amount of purchases and come away with a treasure trove without actually spending so much. Actual chocolate is in low supply, but expect lots of "Ramune" flavor, gum, or snacks that will change the color of your tongue. Charming! There are also more traditional and savory tastes, like dried squid or sweet potato.

It all has a strong Showa-era sense to it, so these kinds of shops are nostalgic for many Japanese people. For foreign visitors already impressed at the low prices of Japanese stores, it takes things even further! You can enjoy a distinctly Japanese experience, find some surprising treats not sold elsewhere, and do it all for a pittance. I make no claims for the health benefits, though...