Worry Warts by Morris Gleitzman
"Dear Mum and Dad, This is just to let you know that I took the torch, the hammer, the gardening trowel, the plastic strainer, the chocolate biscuits and the stuff that's missing from the bathroom. So it's OK, you haven't been burgled. Please don't worry, things are looking better than I thought opal-wise. Love, Keith" What does a kid do when his Mum and Dad are worry warts? Make them rich, decides Keith. Very, very rich. It's a brilliant plan - if it works.