Those look like 12 packs of thick glass, judging from the sign, 12 oz bottles, so about $1.35 a bottle. Although the bottles look larger to me, like the 1/2 liter bottles. Not a terrible deal. It may not be worth it to everyone! It is to me. It is just fizzy water. But if it encourages me not to drink a diet coke, it is worth it!
I went by Total Wine today in McLean, VA and finally scored. They had liter plastic bottles for $1.89 a piece and I think what we are looking at above for $14.99. I bought a couple of the latter. Not as good as the Costco price, but at least they had the stuff. The guy a the register told me they had just started getting Topo Chico in again. That for months they had had none in the store.