Biggest "bang for the buck" audio gear you have owned(in your history)?

This is a great question; one that touches the nostalgia vibe. Not sure this qualifies as best bang for the buck, per se, because, as an impoverished student in 1972, I should have spent this money on my education, instead of my first serious sound system. However, love of music made me do it! So, for me at the time, I guess it was money well spent because this sound system, these components, served me very well for many, many years. The scene of the crime was Tech HiFi in Cambridge, MA. I parted with $350 for a Sansui 2000X and, as best I can recall, around $160 for a Phillips 212 with Shure cartridge. In today dollars, that would be approximately $3,233. I skimped on the speakers, a pair of Studiocraft bookshelves. Can't remember what I paid for those but do remember the entire tab coming to less than $600. A year later, because of the trade-up incentive Tech HiFi offered in those days, I upgraded the Studiocraft with a pair of Ohm C. I upgraded the Sansui (still have it) and the Ohm C in 2001 and the Phillips in 2018. The Ohm C had been re-foamed once and the Philips had a minor repair in the mid 1990's. The Sansui has never been repaired or refurbished but its capacitors & transistors have given their best. How's that for value and solid engineering? Many audiophile friends with systems twice and three times the cost of mine often scratched their heads when visiting, wondering why this system sounded better than theirs. As our parents were fond of saying: "They built 'em good in those days!"

For many years- decades- the biggest bang for the buck was Black Diamond Racing Cones. Now it would be Nobsound springs.  

Only other thing that can touch those was Krissy's Total Contact.

NPS 1260

Era/Peachtree D5 bookshelf speakers. Super impressed with these small speakers designed by Michael Kelly. Found a new old stock pair for like $350 bucks. Had Danny Ritchie of GR Research build new crossovers for them. Don’t use them anymore but they’re just too good to get rid of. They’re my biggest bang for the buck though I’ve had much bigger bangs for much bigger bucks.

My Polk lism707 returns got them for $1400.