Does it need a mic or not? That is main difference between Headset/Headphones
you can add a modmic to most headphones so distinction isn't really there
The only high quality microphone that you can easily attach to any pair of headphones. Enjoy the audio quality you prefer, while adding the stellar clarity and communications capabilities of the ModMic.
antlionaudio.com
I don't know Headsets really. Or less expensive headphones (Though 300USD is almost 600AUD so not really cheap.)
this might help:
His channel would be one to look at as he largely reviews audio for gaming
As for Headphones under 300...
I believe you can get this for under 300 now:
The Edition X gets a major upgrade The HIFIMAN Edition XS expands on its predecessor’s achievements with several major upgrades. Featuring Stealth Magnet Technology and the company’s NEO Supernano Diaphragm, the Edition XS produces a wide and natural soundstage. The NEO Supernano Diaphragm is...
apos.audio
which is a really good price since they were 500 last year.
But its open back and you probably want closed...
I almost bought these last year until I found a better deal.
The next set of IEM I am getting are available locally which is nice, no international order needed. Buy them next month, not ordering anything for remainder of year.
Only plan on 2 headphones next year. Both are available in my country for a change. Just need to save up for them. The IEM above are one of them, the others will take a few months to save up for.