What are those medals usually made of? Gold, silver, bronze, copper...
Medal, or medallion;
a small usually metal object bearing a religious emblem or picture: a piece of metal often resembling a coin and having a stamped design.
They are also known as "rounds", "tokens", and "bars". (call them anything but a "coin" unless you want to risk legal troubles).
...and medals are an earned item, not a winning.
Fancy Shmancy Fine Print: