Average Per Week and Month. Males between the age of 16 and 24 who worked part time earned a median weekly income of $177 in 2011, according to the Bureau of Labor Statistics. Females in the same age category earned a median weekly income of $170 in 2011 working part time. In the state of Minnesota, teenagers earned an average of $643 per month across all industries in the summer of 2010. Those working in the food-service and accommodation industry earned an average of $559 per month in the summer of 2010.