We got 2 inches of rain a few days ago and I collected it in the old wash tub. That netted me 6 gallons of water to use in the garden.
This not only saves money on water, but also demonstrates in a real-life way to Brady the principal of reuse and recycling. You could even do this for house plants.
I just need to get more wash tubs and save even more! Below is Brady's watering can next to mine, and the milk jugs I save (more recycling!) to collect rain water.