The cheapest way is to find some cheap, food-safe container(s). Put it into your basement and change out the water every 3-6 months. 55 gallon rain barrels can

The cheapest way is to find some cheap, food-safe container(s). Put it into your basement and change out the water every 3-6 months. 55 gallon rain barrels can often be found subsidized and therefore cheap. Keep a bunch of camping iodine drops around and you are set.