Actually, an auction is a quick and easy way to find market value. My experience is that stereo gear goes for less, maybe as little as half the prevailing e-bay prices. If you get something cheaper than that, chances are you purchased from an uninformed seller.
I would define insane e-bay value as the atypical result of a bidding war, like the L100s that went for over $1200 not too long ago. That was an amount that really stood out from the other sales around the same time period.
A look at completed auctions reveals a range between $400 and about $800, with more at the $400 end of things, so an average is probably around $475. If I were wanting a pair and paid $200 or less locally, I would consider it a bargain, especially knowing that if I had sold them on e-bay last week I'd have gotten at least $400.