The water bricks are great. What I like about them is that they interlock when you stack them, they are very tough, and don't leak, even when stored flat. I would recommend getting a second spigot if you buy several of these, as the wide mouth is a bit hard to pour without one.
As a bonus, they are 2.5 gallons, and my wife can move these around without much trouble.
Amazon and many other places sell these.