[alliejay]

This is not a specifically accessible related answer but depending on how many days you will be there and how much you plan on traveling by rail, definitely consider the Japan Rail Pass as it can save you money compared to buying individual train tickets. You can only purchase it as a tourist to Japan (citizens and residents don’t qualify, I believe).

Have fun!

[schroth-sensei]

There are useful items at 100円ショップ (Hyaku En Shops or 100 Yen Shops): Like Dollar
stores in the US, you can find many inexpensive things here
that you may need for daily life (for both long or short stays). During my recent long stay in Japan I frequented
one conveniently located at my closest train station, and all the stuff I
bought didn’t feel cheap or break easy. It was great for laundry clips, detergent, dish-washing soap, pens, paper, utensils (found some awesome long-handed forks
that work better for me, so I bought 3 I still use!), etc. They also have helpful stuff for
travelers like many cell phone cords/charging outlets, umbrellas, Pancho’s, hair
ties, brushing & flossing items, or even candies and small items that can be
fun souvenirs.