What are/were the best sounding cheap components you have ever had?

Vintage Equipment, Intended Overhaul, Great Sound and Great Value

I took a chance on a vintage mx110z McIntosh Tube Tuner/Preamp. Enjoyed it as received for a few years, then sent it to Audio Classics for Overhaul. New capacitors/resistors/rectifiers/align tuner/all new gold plated rca jacks. 

Now, I advise: Prearrange with Audio Classics (or ____?, McIntosh: send directly to Audio Classics; They Overhaul it, ship to you.

You buy, you pay directly for UPS to pack and ship; seller simply drops it off unboxed at nearby UPS in your name.

i.e. my mx110z mid 2019, bought $1,200. Overhaul $1,200. Total $2,400. (plus tax/ship, any equipment needs that). Costs have gone up, so has new stuff. It is a tremendous way to get Old World Sound Quality and Full Features with New World Overhaul, for Far Less than New.

The KLH compact units were wonderful as were their radios.

Boston Acoustics T-830 series II speakers circa 1993. Still sound great!

Stax SR4/SRD40, although it seemed like a fortune to a kid just starting his career in 1975.

I bought Pioneer SP-FS52 speakers designed by Andrew Jones at the recommendation of my brother-in-law for some cheap speakers in a secondary system.  I knew they were superb for their price pair with an old Hafler DH-200.  However, I recently brought them into my main listening room for some fun and Wow!  Admittedly, I am driving them with a Cary Audio SLI-100 which is probably unusual for such budget oriented speakers.  Nevertheless, these speakers have no obvious weaknesses and punch so far above their price point that it is hard to believe.  Hats off to Andrew Jones.  He is a master and the crossovers are dialed in.

Townshend Rock II turntable

Second hand Thorens TD150 - add some chassis damping, a solid base board, new springs Armageddon PSU and a decent arm and you aren‘t far off a an early Linn

Robertson 4010A power amp - a Krell on the cheap if you get a good one

Marantz CD5000 - outperforms many high priced CD players, especially if you perform surgery and take the output straight from the DAC