I've tried a few different pairs and the pricepoint where sound quality becomes "good enough" seems to be somewhere around ~£35. If you want a microphone too, bump that up to ~£50.
My _purely anecdotal_ experience is that cheaper headphones tend to work well for pop music, likely because their reproduction range is bass heavy. Sadly the moment you want to add podcasts into the mix, the balance is off. Spoken word just sounds stuffy.
When I'm not on the move, you can pry my AKG K270 off my cold, dead hands.
I do see a difference between the branded ones I've used (mostly Panasonic and the Samsung AKG one that comes with phones) and the cheaper generic ones I've tried out here and there
There are some very crap ear buds around (e.g. Norwegian Air's freebie handout ones are quite possibly the worst things I have ever used), but I was pleasantly surprised by the sony ones. No relation - just a satisfied customer.
1 - https://www.sony.co.uk/electronics/in-ear-headphones/mdr-ex1...