What about a paper route? My 10yo, 11.5yo and just turning 13yo all have one.<br>
Being a mother's helper or babysitter at that age could make some money.<br>
Or cutting lawns/doing simple yardwork/gardening?
Is your town walkable? How about running errands (small grocery trips, post office, dry cleaning) for neighbors. What are his hobbies/interests? It's always good to try and find a way to make money doing something you enjoy. If he likes cooking, maybe he could make meals for busy families. Video games? Maybe he can offer classes for younger kids (as a way to give parents a small break---a mother's helper w/ a twist). Reading/books? How about offering to help people organize their bookshelves or making books on tape to sell?