Installing TV sets on display in a tiny independent electrical retailer at the local shopping parade. Extra bonus points were heading out on my BMX to provide on-site 'technical support' to the old boys who couldn't figure out how to tune in their TV to their VHS (that'll be UHF channel 36, sir).
It was just on Saturdays for a couple of years. I think it probably earned me just enough to buy a couple of cassette albums at Woolworths each week.