I've heard vanilla, tea tree oil, Avon Skin so soft, vinegar....
I think the theory behind all of those scnets is that is messed with mosquitos ability ability to sense the CO2 in your breath that attradcts them to you.
personally, I don't think DEET is evil if used appropriately. I found the following article that gives some info on DEET and Kids as well as some natural alternatives CDC finds effective (that I didn't know before...)
Are Insect Repellents With DEET Safe for Kids?