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