I truly struggle (in the US) to find 12oz glass-bottled sparkling water that's cheaper than some beers sold in 12oz glass bottles. One might think the glass is making it expensive, due to the weight, but then why are some beers in glass cheaper? It seems like, at worst, non-famous sparkling water ought to cost slightly less than the beer does, but it's typically about the same or a little higher, something like $1.15 or $1.20 per bottle purchased in quantities of 15 (and more like $2 or more purchased in singles!)

(why not buy larger bottles? I prefer small ones because I don't always want to drink an entire 750ml of fizzy water in a single day, and it goes flat if left overnight; I do buy plastic sometimes but the discount over glass is so tiny that it's not really meaningful, and I prefer glass, both due to vague uneasiness with plastic and because if I end up drinking out of the bottle rather than a cup, glass bottles feel nicer than plastic)