Octave is a great project though since it is Free (in both senses of the word) it would be nice if people who end up saving €120/year on ML could consider passing a portion of those savings on in the form of a donation.
Yeah the home MATLAB license is the most expensive software I've actually bought. Octave is... okish. But Matlab is like 80% plotting and Octave's plotting support is pretty terrible.
In my opinion there isn't really anything that competes with MATLAB for the things it is really good at. Numpy is shit.
If you really can't afford £120 for MATLAB then I would say the next best option is Scilab.
Now we just need SOLIDWORKS to introduce a decent hobby license. They added one recently but it's subscription only so screw that.