This Avex Marco Double Wall Auto-Seal Water Bottle drops from $19.99 to $9.99 with free shipping while supplies last at eBay. This is the lowest price we found anywhere for these water bottles, which go for $18-$20 at other sports and outdoor stores (for example, see here). They're available in 3 colors, are BPA-free, and dishwasher safe. Note: Amazon now has the blue one at the same price with free shipping w/ Prime. There is no sales tax (except CA).