Killer used integrated for

+1 on Rega Brio. I just sold one on another marketplace. 

Also, killer is not the word I would use for any of these.

Ps audio sprout 100. 

'Killer' is a matter of perspective!For a good value in new, how about the Yamaha integrated amps in the price range?

I've been looking for something similar. Mine is specifically for a pair of EPOS M5 speakers which are 88db, 4 ohm bookshelf speakers. (Recommendations welcome.)

A few things that have been on my radar are the PS Audio Sprout, the NAD 3020, the Emotiva TA-100, and the Nuprime iDA6 which is on clearance for $350. You can probably get to some things a bit higher than this list if you are looking used, but of course that's dependent on what you actually find available used. 

https://www.usaudiomart.com/details/649634586-vincent-audio-sv129/ $385 used, down from $1k.