AKG M220 Pro

The overall sound is clean and balanced. The highs are clean and not sibilant or in your face. They are fairly recessed but have great extension which keeps the music alive and not sound dark. Hence these make a great candidate for long listening sessions without fatigue. Vocals sound amazing in these. Been listening to a lot of Jim Morrison, Sam Smith and Freddie Mercury lately and I can definitely confirm that the vocalist takes a step forward. The mids are surprisingly very well detailed and cozy. any vocal based music will sound fantastic in these. the presence of a good amount of midbass which doesn't bleed into the lower mids gives a good heft to the sound . The drawback is that it seriously lacks the sub-bass punch and rumble but hey, you're already getting much more than your money's worth.
Soundstage is fairly well (lesser than the crazy Koss KSC75X at 17$) but the imaging is quite good.
Surprisingly at 55 ohm and 91dB/mW this is classic AKG i.e needs more power than it should. So an amp is absolutely must to even get sufficient volume. I have to keep it at 12 o' clock on the Magni 3 high gain all the time. On quiet recordings I have to keep it at 2 o' clock.
The comfort is crap if you're using stock pads. The stock pads are shallow, hard pleather that doesn't breathe. Gets sweaty and hot very soon. A brainwavz XL Round Perforated pad is recommended (the non XL is a tight fit and hence not recommended)
For 50$, this is epic, give it a try.