I'm going to concede on the particulars of how low the price was because it must have been just a killer loss leader in-store sale at walmart - the cheapest I can find now online is ~$7 for the same flat of 35 17oz bottles.

I am, however, going to disagree with how much water. 2 gallons of water for a single person each day seems to be more than just excessive for drinking water. Even if I was drinking 17oz each primary meal and another upon waking and upon going to sleep, that still leaves 171 oz remaining to reach 2 gallons.