When I want to listen to mp3's, and I don't often, I use a cheap little Chinese device.
You will probably laugh, but I still use an SE/30 to this day.
I have a IIfx rom in it making it 32bit clean. It is maxed out to 128mb of ram and has a 2 gig SCSI hard drive in it as well. I hacked OS 8.1 on it years ago and use it to only run an old copy of Opcode Galaxy Plus librarian/editor with an Opcode midi patch bay off the printer port. I have a lot of old synths and samplers in my project studio, and they just don't make synth librarians and editors anymore that will work with newer machines and older synths and samplers.
This Mac has been running strong with only a hard drive replacement for over 20 years. Apple just doesn't make machines like that anymore even after Jobs came back. The Apple I knew has been dead for many years. This is a new company more interested in a lifestyle and multimedia than in computing.