$8 is a little high based on a quick search of digikey, but high capacitance high voltage caps (even polar ones) get expensive ($5 per). I've had to use 600V 3300uF ones before and they cost $40 and are the size of a coffee mug (maybe even a little taller). It gets even more expensive as you look for low ESR ones.
Personally, I would have back-up functioning power supplies and then figure out how to repair one if it breaks.