What's safe to put on my kids to keep the ticks away?

 We live in a subdivision. There are no woods for my kids to play in. Last yr the ticks were not bad at all. This yr my kids seem to get a tick on them everytime they go outside. I've sprayed the chemical stuff on them which I don't like to do and they still get a tick on them. My poor middle child seems to get the ticks the worst. He's got little bumps on his back where I've had to take them off. I'm just so fustrated with all of it. 

Is there something that you have used that has worked wonders for your kids?

Avon in the UK do a skin so soft it's the fresh one that's pretty good, are you making sure you get the whole thing out? Mine have had ticks before from camping and not been left with any bumps on the skin. Poor wee man hope you find him something that works and keeps them at bay.

http://health.thefuntimesguide.com/2007/06/permethrin_for_ticks.php

 My grandmother swears by Avon Skin So Soft. I remember her rubbing me down with it as a kid and I don't ever remember having any ticks on me while my cousins had tons on them. She still uses it on her dogs to keep ticks and fleas off of them and it seems to work.