I use a poncho. I know, most people don't like them. But, I live in a really dry state. If it rains, a poncho is generally plenty adequate. I can also throw it over the back of my pack and keep it dry as well. If it is windy, I put a rope belt on. I just haven't had a bad experience with my poncho.

The other day, a local outfitter had a sale on kid sized Kelty ponchos for $10 each. I bought 3. They fit my 5 year old, my 8 yr old and my 9 year old. I have two adult sized ponchos for my 12 and 13 year olds. I think they cost $20 each.

Looks like I posted at the same time as Pika