Streaming music from a service like Spotify or Tidal is great, but it's not always convenient. You'll need a solid internet connection, and while you can download songs for offline play, once you stop paying the monthly fee, access to all of it disappears.

Buying digital music such as MP3s makes sense for a number of reasons. It's yours to keep and put on whatever device you want, and it better funds the artist and labels who can then keep making more music.

Whether you're looking to buy a music single or whole albums, here are the best sites to visit. We'll start with the biggies -- iTunes, Amazon and Google Play -- and move on to some of our favorites that you may not have heard of, like Bandcamp.