By any measure, Appalachian Spring by Aaron Copland is one of the great American works of art. But in 1944, Copland was paid 500 dollars for writing it. Not much for a future classic. But looking back, Copland said, "they needn't have worried about the amount. Five hundred dollars seemed like a lot to me in those days." On Friday's Performance Today, we'll hear the Orpheus Chamber Orchestra play 500 dollars worth of music by Aaron Copland.