10 bucks headphones can be worth it, if you PEQ them and they can be PEQ'ed in the first place: audiosciencereview.com/forum/index.php?threads/9-headphone-review-sony-mdr-zx110.19484 (ur welcome).
Even majority of very expensive, known-brand, headphones (>5000 bucks or more) need to be PEQ'ed (depending, or not, on the preference curve you want), or can be bad even with PEQ applied, and there are 30 bucks headphones, that don't need to be PEQ'ed (depending if they fit your reference curve). So, there's really no golden rule, except to measure them using quite expensive equipment.
On Linux, Easy Effects is commonly used, see tutorial (from signature) on how to apply the PEQ text config files on the mentioned site.