I've never had the budget to purchase a pair of decent and audiophile-approved headphones, IEMs, or speakers/monitors, so starting a few years ago, I started hunting for the best quality sound I could get for around $50. I started with a pair of Sony MH1Cs which I thought were pretty great, as I was able to find them on Ebay for about $60CAD. They had a great flat sound that responded fairly well to anything I threw at them, and they were amazingly comfortable! The only complaint I had (as every. single. reviewer did), was that the flat J cord was stupidly... stupid. Enough said.
This past year, I wanted to see if I could find some IEMs that were newer and "better" than my Sonys, so I did some hunting and found the Lker i8s. I was pretty skeptical of the no-name Chinese-made earphones, but after listening to them for the first time, I was blown away. They ARE bassy-er than I was used to, but because of the balance and clarity in across the mids and highs, I quickly became accustomed them, and they have grown to be my favourite pair so far. I wonder if anyone here has come across them as well..?
Another notable mention is a cheap $15 pair of Philips IEMs that my wife had. I had forgotten my IEMs at home so I settled for borrowing hers. I scoffed at the thought of using cheap earphones and prepared for the worst, but I was surprised at how clear they were! They obviously weren't amazing, but the mids and highs had a crisp, clear sound to them that did a decent job of carrying vocals through.
Anyways, would love to hear your stories of your great finds!