I have used the Cancer Society After Sun Gel for a while now and always have it in the house year after year.
When the children have gone on camps, I've explained to them if they get burnt then to apply it gently and they love it as it's extremely cool and soothing. The Aloe Vera gel absorbs into the skin making the burning feeling from the sun easier to bear. A must have in the cupboard or to take away on holiday. Inexpensive and a little goes a long way.