Free mint water

Do you pay upwards towards $1.69 for a bottle of mint water?  If you have mint growing in your backyard, you can make it for free.  I don't recall where I saw this recipe, but just pick 1-2 cups mint leaves (I use spearmint), bruise them a bit, then add them to a gallon of water.  Store in the refrigerator and a couple of hours later, you have mint water.  Very refreshing!