I run the VLC app on my mobile devices, which allows me to spawn a web server served off the mobile device that I can connect to in the browser on my laptop or desktop PCs.
I can upload raw music files (mp3, ogg, etc etc) onto the mobile devices seamlessly, and it categorizes them by album.
I only ever buy full album or track digital downloads from bandcamp or Amazon music. Zero DRM, just straight archive files of mp3s usually (bandcamp lets you select which audio file type for a long list of options).
For unknown music, you usually pay what you want or pay a small price like $1 on bandcamp, which is almost always worth it even when just testing out some music I’m not sure if I’ll return to yet or not, especially compared with the negative externalities of subscriptions with Spotify.
I consume probably 5 different $10 albums per year and maybe another few hundred or so LPs or individual tracks at about $1 each. My music budget is probably about $250 / year, which is roughly twice the price with Spotify premium.
I could go on another rant about how Spotify’s content discovery / collaborative filtering offerings are extraordinarily poor and provide genuinely negative value for me when I previously used the product, but regardless I feel very happy to avoid Spotify’s negative externalities. That is well worth an extra $10/month of Spotify-avoidance-fee to do it with non-streaming options.