My question is not about streaming but physically downloading music to be stored on your Android phone.  There are cloud based services that work well (Google Play Music, soon to be Youtube Music, Amazon Music, and of course services like Spotify...)  These services tend to lock you into the system you are playing music on.  You need to cast music to a system or have something with Spotify built in.  I have a few different systems in my own house as I have setup demo equipment from various companies.

The other thing is I don't listen to all that new music and do not benefit from paying monthly fees for a streaming service.  For my use, having music on my phone works best for me.  Currently, the easiest way for me to download music and get it on my phone, ironically, is to use iTunes to download, convert it to an .m4a file in iTunes, copy/paste it to a new folder for ease of finding it later, and then importing to my Android using Air Droid app.  It's not a terribly long process but requires me to get on the computer to download music.  All of the services I have tried that do allow you to download music, is more of a cached deal where it allows you to play music offline within their app, but not from outside of their app.  I was wondering if anyone has an easier method, or simply a method to do it all on the mobile device without having to run to the computer to download the songs.