It is, as you surmise, SO dangerous to ask a quesiton like this... since it's exactly HOW some of those prices get so stratospheric in the first place! Consider, for example, the EICO HF-81 (a very good amp) or, better yet, the EICO single ended, stereo AF-4 (a really cheap amp). The former is quite expensive because of some good buzz at the Klipsch Forum and other places some years ago. The prices that the latter fetches on eBAY astound me! It's a perfectly OK little amp, but...
As to your question: as Chad said, luck (and patience) is probably the best way to find something decent that isn't outrageous. I very much like the console amps from Magnavox, but they're not really bargains from a place like eBAY. Thrifts, fleamarkets, garage sales, and your town dump/swap pile (if so equipped) are great places to look, indeed. Consider buying two monoblocks rather than a stereo amp, even if you have to do it piecemeal. Example, with luck and patience, you could buy two EICO HF-12's on eBAY for considerably less (possibly even half) what a single HF-81 would cost... and an HF-81 is essentially two HF-12's in one cabinet.
Finally, I'd opine that tube amps from the "S" companies (Scott and Sherwood) are likely better values than 'equivalent' pieces from the "M" companies (McIntosh and Marantz)!

Also worthy of consideration are h/k, Pilot, EICO (mentioned above), Channel Master (!), VM (Voice of Music), Radio Craftsmen, Allied/Knight/Radio Shack, Lafayette... must be more, but I think these are some good brands to look for that might not have the sticker shock of some better-known brands.