If you're okay with learning on a guitar Ben Levin's* "Music Theory from the Ground Up is an excellent series. He breaks down everything into really small pieces and its a lot of fun to learn from him.

Heres a link to the YouTube playlist https://www.youtube.com/watch?v=Q3yqUeiMn_g&list=PLJTWoPGfHx...

*I am in no way affiliated with this guy, and to my knowledge he does not charge for any of his lessons anyways.