I walked into Wally World today to get some cinnamon. (It's good for the heart, and flavors my oatmeal.) On the way out there was a big bin of bottled water, not cases - individual bottles, and not even cold. The sign indicated that they were inexpensive, but they were still 50Ȼ each. When you buy a case of 24 for $3.00 that's about 12 Ȼ apiece.
But the real cost isn't the 12 Ȼ or 50 Ȼ or $1.50 that you might pay for a bottle - the real cost comes at the expense of the environment. Finish the bottle and throw it away - wherever you happen to be, and if there's no recycle bin it goes in the trash or on the ground. Recycling costs money, but not recycling costs space. Those plastic bottles don't magically disappear overnight, they're not biodegradable, and we can't even begin to know what kind of toxins they might release during the 450 years (450! And some sources estimate up to 1000 years) We can't begin to know because even the earliest of these bottles haven't finished decomposing yet.
Yes they're convenient, but maybe there's a better way to get the fluid we need each day than to throw bottle after bottle into the landfill.