Bitwig is on sale right now through Mid January 2018, 80 € off, for 299€. I have used Ableton in the past, then Bitwig after it was released. And I don't see myself going back to Ableton any time soon ;)

I believe you could always use it fully in Demo mode, and still can, unlimited number of tracks - "only" export and saving being deactivated. BUT there was a workaround back then, saving your tracks with settings and (clip) automation into your library. And then simply recalling the library saves in a new session :) A little tiresome, but if you are really organized you could technically build a lot of track, and export it later or with someone who owns the full license.

Not sure if that still works though.