100 yen – Equal to about $1, this coin made of nickel and copper has many uses. 100 yen coins are aptly used at 100-yen stores, and laundry and vending machines. 500 yen – Basically a $5 bill, this is the largest and most valuable of the yen coins. A 500 yen coin can be used to buy a simple lunch such as a bento box.