Dave Bonta turns the loose change in his pocket into a struggling music trio. A bad penny, a wooden nickel and a single lousy dime are all worthless or nearly worthless, and each one is stuck with a stock phrase: the bad penny always turns up again, the wooden nickel is a fake. Here they try to play together, and it goes about as well as you'd expect. The penny repeats the same tired riff, the nickel is flat, the dime can't keep time, and none of them can manage the chord changes. The jokes are puns, and the gentle silliness is a big part of the fun.
The ending shifts the tone. The speaker calls it sad when "bit players get big / without paying their dues." The title, "One-hit wonders," suggests this is a dig at undeserving fame. The speaker sounds amused, a little weary and a little sarcastic, as if the coins stand in for real acts that rose too fast. The mood is light and playful, with a dry bite underneath.