Free iOS music apps that allow queuing?

I don't use Spotify/Rdio/other music services - I just want to be able to queue songs in my iPhone's library so that they will play after the current song or after the next few songs that I have already queued.

I know that playlists kind of solve my issue, but they're not as flexible and I'm sure you understand that there is a difference.

Preferably a free app. Hopefully a pretty app!