Yeah, I'm not sure what the scenario was here, but I'm guessing they replaced a broken spoke, charged him $3 for the spoke and something else for labor. Whether the "overcharge" for the spoke is fair or not would depend on what they charged for the labor.

Stuff like that would probably cause me to shop around next time, but if this was a matter where they let me jump the line and get it done so I could do my day's ride, I probably wouldn't think twice about it. Then it's just like "overpaying" for something at a convenience store--I'm paying a small premium just because it's there when I need it.