Buy gifts for homestay family/ etc.
The Japanese have a very gracious culture. While they may not expect a foreigner to bring a hostess gift, it is a great way for one to show respect (and a way to negate the "Ugly American" stereotype).
How to present a gift: Make sure when you present a gift you give it with two hands, palms up and slightly bow your head (it is a sign of respect in Japan that goes a long way)
Best advice: get something that is specific to your town. You will realize that Japan has just about everything so something that has a cool story behind it would be ideal. For example, I have a friend who came from Hawaii and brought boxes of chocolate-covered macademia nuts that were a big hit, just like sea-salt toffee from Nantucket would be a great idea. I think food in general is a good way to go (especially chocolate) because it is small, lightweight and universally appreciated.
In Japan…..What to bring back home (aka The best souvenirs)
You are obviously going to buy gifts for friends and family while you are abroad but just remember that even if it is cool in Japan, the best gifts are those that people can actually enjoy and that can’t be purchased at the local Asian market down the street from you in the states.
Best advice: For your closest friends, get a t-shirt from a festival, sporting event, concert or museum. While those can run about $30+, I found that the greatest/coolest/perfect gift was none other than KitKats.
You may be interested to learn that Japan is the only country that has a huge selection of KitKat flavors ranging from blueberry cheesecake to orange to green tea. In fact, many cities have a special kitkat flavor. For example, when I went to Nagano I got KitKats that have a special apple flavor that the city was famous for. While these special kitkats can be a bit expensive (700 yen or so, $9ish), many supermarkets have bags of different flavors every month that are only about 500yen.
Click HERE to check-out some of the awesome kit-kat flavors
FOOD - non perishables
Candy: Jelly Beans, M&Ms, Snickers
Chocolate: Hersheys, See's, Salt water taffy, Truffles
Coffee: Local kind and even Starbucks are welcome
Regional foods -- such as maple syrup (VT), honey, bbq sauce (Texas)
Tea: Constant Comment Tea by Bigelow is grown 100% in the USA and is based on a Colonial recipe
Spices: special salts, made regionally
Soups and dips in pouches
Trader Joe snacks
Jellies, jams, marmalades
In Connecticut: Pepperidge Farm, Milano Cookies; Bigelow Tea; Local honey
CLOTHES & Hats - American icons
Sports Teams - especially Yankees and Red Sox
American rock bands
American car manufactures
Coasters - particularly that depict something regional or American
"Cute" things for the home such as Anthropologie makes. Japan home wares are not "cute", unless they are for children. So placemats, napkins, small measuring cups, etc. in charming prints and shapes are enjoyed.
-Lightweight shopping tote bags from your area.
Oil of Olay products
Locally made soaps, lotion, balms (though not too heavily perfumed)
Legos (very expensive in Japan)
Bob The Builder
Anything made by an American company
Anything from your local team or a team
For instance, Stanley tools are made in CT., so a small flashlight by them with an explanation
About your town or a region you love