not very good ones, when i was 14 i worked as a paper boy, just ask at ur local newsagent or find out about one of those free local newspapers/leaflets they normally need ppl delivering
Depends where you live - when my daughters were 12 + they had jobs mucking out at local riding stables. Seaside places are easiest for youngsters to find jobs, but be careful not to let yourself be exploited.
Possibly car washing, or garden weeding. Why not prepare some little posters, decide how much per hour you will charge, and put them through the letter boxes of your neighbours?