$35. That's a reasonable price to pay for those of us who have computers that lack these outputs and the motherboard headers for them.
https://www.smsl-audio.com/portal/product/detail/id/788.html
I ordered a pair of Massdrop/AKG M220 headphones. From what I've read, they're the same as the AKG K240 Studio. Can the SMSL Idea drive them to a listenable volume? From searching around for info, it seems that they can, but I'm not sure.