Write letters to government officials in your city/town. Your government should have a website and emails for everyone in office. Send letters to all who apply (especially to education and international affairs people) telling them about your role in Japan and ask if they have anything they can give you to support education and internationalization, such as books, flags, pins, posters, CDs, etc. I got TONS of free stuff by doing this and my kids loved what they got. Anyone who got a pin had it on their pen case all three years, and it helped them to remember my non-famous city/province name.
You can view a copy of the letter that I sent here:
JET Programme Forums View topic - How to Get Started
simply insert your details and send away!
I give out my prizes in my first lesson. I do a true and false quiz game and have students guess answers when I say something false. For example, "I am from the United States." (False) "Where am I from?" (Correct person gets a prize).
I also give stuff away for Canada Day just for fun.
Another great prize is money. Bring a sack of clean pennies/nickels/etc. They're good for cultural education, are super cheap, and kids love it. I had a small collection of special quarters from Canada too that was a great prize/token.
Prizes for me are more about giving things that are interesting rather than being an external motivator (although some external motivation has a place). Even after a game, if kids come to me and want to see something I was giving away and asks questions about it, I'll usually give them something also.
Once in a blue moon I'll make magnets that correspond to games we play just for fun. Back in Canada when I taught high school (senior 4/grade12), I decided to put stickers on work that got 90% or more for fun. My students were surprisingly excited about it because of the nostalgia factor of getting stickers in elementary school. Some worked harder to get the sticker...lol To be honest, I was the same way as a kid. Some students want proof of success. There are other ways to do that too, like stamps (or your hanko), using graphs to chart their progress, and so on. Sometimes if I have a goal, like exercising, I'll give myself stickers on my calendar for days I do well. We can't deny our craving for some forms of external motivation!