I used my old android phone with 512 card. Mp3 dedicated devices today are pretty shit unless you spring for $200+ ones. I tried 2 of the $50 ones from Amazon, was better with an old ass iphone 5c I found in a drawer. Then you can use any audio app to play your files. At the time I used media monkey before I setup my PlexAmp server. Even then you can download massive playlists locally, no need to stream it, similar to old school iTunes.