Used PS Audio amps (200, 100cx, etc.) run in that price range. They can sound a little hard at times however (although Paul McGowan claimed to have been using ARC electronics to voice his equipment). The Bryston is a good choice, too - I used a 3B for years with my M-L Sequel IIs and (now-extinct) GNP 220s. I'd also look at the Marantz MA-700 blocks; they're pretty cheap, come recommended (haven't heard them myself) and you can save $$ on speaker cable by putting them right next to your speakers.
best used amp for 300- 400
I have a system composed of a rotel rcd970 cd player, rc990 preamp, rt940 tuner, acoustic reasearch turntable with denon mc cartridge and old infinity Qe speakers and am looking to replace my amp an old dying adcom gfa-2. I have heard a rotel rb 980 in the system and it was decent but not great i am trying to find an old bryston 3b but any suggestions would be welcome, my price range is less than $400 including shipping so closer to $350 would be ideal. I listen mostly to classic rock and ska, so i want power and good bass but also want good upper frequency perfomance as well. Thanks