Using your Android phone (and probably Apple) I can search for the Google APP by typing "Voice Search", starting that APP (or leaving "OK Google" turned on), and saying: "Play [Insert song name here]" - the song is located and played.
First time through you may need to set it up and choose your preferred player, second time it simply plays the song automagically. You can cast it to your stereo if desired, you can also choose videos (and send it to your TV if the TV has the capability).
There is the ability to go to your device's storage and play your own songs instead of the version that Google guesses that you want (if you aren't specific enough).
With my phone there was nothing to buy or install, it Just Works™.