Barley tea. Doctrine and Covenants 89:17
DC 89:17 "Nevertheless, wheat for man, and corn for the ox, and oats for the horse, and rye for the fowls and for swine, and for all beasts of the field, and barley for all useful animals, and for mild drinks, as also other grain."
One of my Korean customers introduced me to barley tea. You can buy it in tea bags at Asian grocery stores. I recently bought a box of 30 bags for $2.75. Each bag is enough to make 3 cups, so it works out to about 3 cents per serving. (Cheaper than herbal tea.) You can also buy roasted whole barley (usually found at Asian grocery stores too) and put it through a mill or coffee grinder and brew it in a coffee maker or one of those tea-pots with a built in strainer.
Click here for a recipe for making barley tea from whole roasted barley or how to roast your own barley from pearled barley.
It does need a sweetener though. I prefer honey or raw (turbinado) sugar.
This was brought to mind after an investigator asked our missionaries about green tea. They checked with the mission president, and said that green tea is to be avoided like black tea per the Word of Wisdom.