Really Inexpensive Systems That Sounded Great?

Nothing , at that price point , I just built a second audio system for the Mrs.

it has a Parasound A23+ amplifier shop,around I got a open box $1400, 

AudioGD  demo model $1k very under the radar, 

the very much reviewed Gustard R26, better then my pontus-2/after synergistic purple fuse  local dealer $1600+ fuse, Pangea sig mk2 power cords ,

Wireworld Eclipse xlr Audio cables . Older Klipsch speakers I rebuilt the Xovers 
the Equinox is a lower cost cable option still very good for others on more of a budget.

It sounds like a $10k system all day .having owned a audio store and 40+ years in making system synergy . There are a lot of bargains out there 

My current system. Conrad Johnson PV12 preamp ($500) score!!!!

Super Clef Ribbons ( free!!! ) given to me by the late Bob Gross’s wife from his listening room. Amazing speakers!!!

2 Bryston 3b NPR amplifier that’s bridged to each Clefs ( $500 for the pair )

Kenwood KD500 with Signet XK50 tonearm ( free!!! ) also from Bob Gross personal stash.

The reason I’ve gotten much more free stuff from Bob Gross is that I’ve build new Clefs bookshelf and the TL using all his parts that he had and audio gear he used for shows and sold them  to help Mrs Gross financially.

I’ve built myself a set of his Super Clef and TL and are truly amazing speakers.

Tribbett Stormbox $60 Bluetooth speaker.

I have a pretty tube based system that my wife doesn’t feel comfortable using but enjoys listening to music so I bought her a Sonos powered speaker (about $500) that you sink up w/ your phone w/ any source on it. That could be Qobuz, iTunes, whatever you have.  It sounds surprisingly good w/ just one speaker; nice midrange, some extension on each end & can play pretty loud. I think for what it is, is a great product. 

For the tool using hobbyist, get Akitika PR102 and GT108.  For speakers, PE Morel Ardons.  For source, Wiim Pro and if a turntable is needed, a Teac TN3.  This would all set you back under $2K.  Much less if no phono and no preamp…just plug Wiim into amp, and you’re under a grand!  
For non-kit builders, a pair of B&W 606S2AE speakers and a Rega Io integrated with a Wiim Pro…$1800.00.  To stay under $1500, NAD C316BEEv2 and Wiim Mini.