Unbelievable prices at the moment on Amazon for two excellent items that I own:
Sony MDR-ZX110 Headphones w/mic and pause button: $15 https://www.amazon.com/gp/product/B00OUX6U6G/
Subynanal USB-C Dongle DAC/headphone amp: $3 https://www.amazon.com/dp/B08817XKSW
A dongle DAC is pretty much a requirement for those who prefer wired headphones for their phones. At only three measly bucks, the DAC’s specs aren’t state-of-the-art, but the sound is excellent, the noise floor is silent (no added hiss), and there’s plenty of volume with all of my headphones and IEMs I’ve tried.
According to Amir at Audio Science Review, equalizing the Sony headphones (for the Harman target frequency response curve) “produces reference quality sound!” You can do that automatically on an Android phone, using the free Wavelet app. (I sometimes prefer the un-equalized sound.)
The sky’s the limit on expensive audio equipment, but for most everybody there’s no need to spend more than $18. Don’t need the mic and pause button? Then the headphones are only ten bucks. I’m not limited to these two products, but if I were I’d be perfectly okay with that.