The Glaceau Smartwater Bottle can be found in nearly any gas station and grocery store in the U.S. It's technically the water inside this plastic bottle, but the bottle itself is ideal for backpacking treks. Offered in a handful of sizes -- the 1L size being the most popular -- the Smartwater Bottle has a standard threaded cap that fits some water filters, has a narrow body to fit in backpack pockets, and is surprisingly durable. All with a $1 (or so) price tag.