I worked in the office of the factory where my father was plant engineer. Mostly I compiled the figures that went into the payroll. I did some other general office stuff -- substituting for the various workers when they were on vacation. It wasn't hard, and there was enough variety that I wasn't too bored.
Later I got a job in an appliance store. I tracked the inventory (this being before computers), sold small appliances, and "managed" the gift department.
Not super-great stuff for a resume, but both jobs paid a bit more than minum wage, which helped financially.