When I was younger, I had a newspaper delivery round. Although it may not be the best job in the world, it was great as a first one, and got me the money that I needed for the week. This might be worth looking into, as there are many newsagents and press companies who need young people to deliver things for them. It’s pretty much the only type of work that people under 18 can do, other than waiting on, which isn’t to everyone’s tastes.