I’ve bought group 49 AGM batteries for less than that price . . . decent ones with 3yr free replacement period, not junk
And it was very recently
A group 49 battery is huge, next to those little Prius batteries
So therefore, I think the Prius 12V batteries are overpriced by a lot
The only reason I can think of the expense is this . . . it’s probably a slow-moving item, compared to other 12V AGM batteries for non-hybrid vehicles. Therefore they charge a lot more?