He estimates that the new house will cost roughly thirty million yen. - Hän arvioi, että uusi talo tulee maksamaan pyöreästi kolmekymmentä miljoonaa jeniä.
This book costs 3,000 yen. - Tämä kirja maksaa 3000 jeniä.
The yen is the unit of currency used in Japan. She's got a part-time job for which she earns 2,000 yen a month. The yen is also used to refer to the Japanese currency system. sterling's devaluation against the dollar and the yen
If you have a yen to do something, you have a strong desire to do it. Mike had a yen to try cycling = yearning. To have a strong desire or inclination; yearn. See table at currency