Yen sign
On Windows, hold Alt and type 0165 or 157 on the number pad, then let go of Alt.
Copy it
About the yen sign
One sign serves two currencies. Yen in Japan and yuan in China take their names from the same Chinese character, meaning round, after round coins, and both are written as a Y with one or two strokes across it. Inside Japan, prices are more often written with the kanji 円.