PriceBully via eBay offers the Rubbermaid Tritan Refill & Reuse 20-oz. Sport Bottle
in three colors (Green pictured), model no. 7M58, for $5
with free shipping
. That's the lowest total price we could find for any similar bottle by $4. Each BPA-free bottle fits into standard automotive cupholers and features the ability to hydrate you, when you are thirsty (provided you've filled it with a liquid like water - and not something un-hydrating, like sand).
Want more hydration? This 3-pack costs $11.99 with free shipping. At $4/bottle, that's an even lower price-per-hydration ratio.