The amount of one hundred yen (¥100); also used to refer to a 100-yen coin or price of something.
このパンは１００円です。
This bread is 100 yen.
１００円玉を自動販売機に入れてください。
Please put a 100-yen coin into the vending machine.
１００円ショップで小物を買った。
I bought small items at a 100-yen shop.