Early versions of Andrew Ng's ML MOOC used Octave, if you are looking for examples and exercises.
YouTube playlist: https://www.youtube.com/playlist?list=PLiPvV5TNogxIS4bHQVW4p...
YouTube playlist: https://www.youtube.com/playlist?list=PLiPvV5TNogxIS4bHQVW4p...
Using Octave for a beginning ML class felt like the worst of both worlds - you got the awkward, ugly language of MATLAB without any of the upsides of MATLAB-the-product because it didn't have the GUI environment or the huge pile of toolbox functions. None of that is meant as criticism at Octave as a project, it's fine for what it is, it just ended up being more of a stumbling block for beginners than a booster in that specific context.