downloading music

I am a little embarrassed to say that I haven't bought music in probably 15 years. Back then it was CD's. I have relied on FM and XM radio but would really like to get some of my favorite songs instead of buying CD's full of good and not so good songs like I did in the past. What is the best way to download music? My wife has iTunes but I am not impressed. I want to be able to buy stuff and not worry about using apple stuff to play it. I want to easily manage it from my laptop and put it on thumb drives then plug them into my new truck. It has USB inputs for my music.