If you are really into good quality audio, I'd recommend a used

  Fiio M11 Plus

It's really good, but even used about 450 bucks. This might be too pricey, so you could then go for a

  Surfans F20

like already recommended (https://www.rockbox.org/wiki/AIGOErosQK). It has no balanced output, but is about 120 bucks and supports Rockbox.

If you more into Android and streaming, you could take a look at the

  Hiby M300

which is also a budget device, but has a pretty modern Android and is a bit more portable than a smartphone.

Maybe it's also worth mentioning Qobuz (https://www.qobuz.com/), the high res music streaming service. Many audiophiles are into this, while I'm not using streaming services at all.

I personally use an old iPod Nano 7g and as backup device my Android phone with Substreamer / DSub and self hosted navidrome. Not hi-res, I don't need this :-)

another ($250) option is https://www.crowdsupply.com/cool-tech-zone/tangara

> Tangara is a portable music player. It outputs high-quality sound through a 3.5 mm headphone jack or Bluetooth, has great battery life, and includes a processor that’s powerful enough to support any audio format you can throw at it. It’s also 100% open hardware running open-source software, which makes it easy to customize, repair, and upgrade

Do you carry a smart phone?

If yes, then this:

https://f-droid.org/en/packages/ch.blinkenlights.android.van...

will play flac from your phones local storage (you have to transfer the files to the phone of course).

If you want a new device, these are not too expensive and well supported by Rockbox: https://www.rockbox.org/wiki/AIGOErosQK

Or get a used iPod. That's what I did.