Something they must have had in the 40's and 50's. As far as I know, a pennywhistle would be an old fashion term for "a whistle that costs a penny". Go figure. A moonpie would just be a somewhat archaic term for a pie shaped like the moon (circular).
"Now go and spend it on pennywhistles and moonpies!"
by Didda Tinkle July 01, 2004