what are your top "audio bargins" in your system history?

@jusam 

+1 Advents were my first real speakers and it was hard to let them go. They cost me $200 and I had to spend $1400 to get something better sounding.

Used LP's at the Goodwill for $3.....many of them almost mint.  And a set of mint, original, clean and working perfectly Dahlquist DQ 10 for $375.

My Marantz SA7S1 super audio player was a game changer in my system. Got it as a floor model for less than half price and is still spinning discs and sounding beautiful.

I acquired an Audio Research VT130 as a "throw it in" (that would be for free) while acquiring an SP15.  Someone had "adjusted" the left channel tube bias and it was blowing screening resistors. Once that was rectified I was amazed by the depth of stage the old gal had. Free is a hard price to beat. 

Jolida 301 amp, older definitive technology BP series bipolar speakers almost 30 years ago, ESS speakers from the 70’s with the amt tweeter/midrange, rogue Cronus magnum 2 amp, ps audio ds jr (wish I still had for second system), and now the ps audio sprout 100 for a second system.