"Insanely expensive" is all in the eye of the beholder I suppose.
I bought a pair of $6000 Bel Canto REF 1000m amps used for ~ a 40% discount compared to new. THis is the most I have ever spent on a single piece of gear (actually 2 monoblocks).
Given my needs, I would say this was worth it.
I suspect I could have gone with similar amps from Wyred4 SOund for significantly less and gotten much of the performance needed, but decided in this case to not cut corners. Normally, I would upgrade a component more slowly over time to avoid overpaying.