Hi Alexia -- These are modern 50 yen coins from Japan. They are worth face value, that is, 50 yen in Japan. Some of them have differing flower patterns on the reverse side, as shown in our secondary image.
Even though they are worth face value in normal circulation, and collector in the United States or anywhere else may be willing to pay a premium over face to add an example to his or her collection.
For instance, the coin in our main picture is in very nice condition. A collector might be willing to pay $3 to $5 US dollars for it. If it were more circulated, the price would go down.