I buy a 24 pack of 16.9 oz. water bottles, whatever's cheapest, freeze several, and let them thaw slightly and drink them, and continue to freeze more bottles as room becomes available in the freezer. Afterwards, I wash the bottles thoroughly with hot water. I then boil some tap water in a kettle on the stove, and hours later, after the boliled water has cooled enough not to shrink the bottles, I pour the water into bottles. A nearly full kettle will yield three bottles. I again put bottles in the freezer. This is an ongoing process with which I am involved daily. Each day before I leave the shack, I take three bottles of frozen water out of the freezer, place them in a small Igloo cooler which lives in my car, and after some thawing, I have cold water all day long, regardless of where I'm at. For summer time, and for longer excursions away from the house, I have a bigger cooler that's used as needed. After several washes and re-uses with boiled water, the bottles eventually become distorted, and I will buy another 24 pack, but not for quite some time. I have been doing this for years. Other than an occasional splurge for a ginger ale, water and coffee are just about all I drink. I am rarely without several frozen bottles of water, anywhere, anytime, ever.