I have verizon and I have a 2 GB data plan. I listen to music a lot in my car and I was wondering if there is any app that allows me to find my songs and play them in app but the app doesn't use data at all.
The only way you can do this is with the music stored on your phone. If you have a music library you can sync with iTunes and use the music app on the phone to play them.
There's no way to use an on-demand service like Spotify or Songza without using data.