Older audio equipment
A couple of years ago I set myself the task of building a killer component stereo from charity shops. With no single component purchased to cost over $20 CAD. +TAX (Just to make it a little more challenging.)
It took a couple of months, and a lot of self control regarding the price, but I achieved what I set out to do, and the results are amazing. The sound quality is so far beyond what I had come to expect from years of headphones, and earbuds, that I was literally stunned by the difference.
The only downside, is my dog runs and hides every time I go near the stereo. :)