Used Which amp for B&W 802 Matrix series 3 around or under 1000?

Plinius has a warmer sound that will likely mate well with these speakers that can sound harsh if pushed in the wrong direction or with less-refined or cheaper electronics.  This might be a good match for those reasons…

https://www.usaudiomart.com/details/650000157-plinius-9100-with-audioquest-power-cable-priced-to-sell/
 

Best of luck.

Go to hifishark — they list used equipment from all major sites including A’gon.  A further benefit is you can see what past equipment sold for so you can get a good idea of a fair price range for any product.  Happy hunting!