If you don't purchase a license it just asks you to purchase every time it starts up. It doesn't cripple or otherwise limit the software if you don't purchase it.
from their website:
"The evaluation version of REAPER is complete and uncrippled. There are no artificial interruptions or restrictions, and you can save and load projects normally. We believe in giving you a fair chance to make sure that REAPER works correctly with your hardware and suits your workflow. "
I have a very early version from years ago I bought and still use. It's worked flawlessly and does everything the expensive programs do, but for a reasonable amount of money because it's not made by big companies. It used to be a bit cheaper but even for 60$ these days, that's nothing compared to the prices of other software that does half as much.
I hadn't looked at the features in a while. It actually looks like Reaper has a lot more features these days. I think I'll upgrade soon.
As (primarily) an audio person, Reaper is an excellent DAW, even if you buy it. (Unless you make $20,000 or more using it, it's only $60.) It's not the prettiest or the most intuitive one out there, but it has all the powerful features under the hood as the big boys.
Rosegarden Audio and MIDI sequencer, score editor (so it is good alternative to sibelius and other notation software), and general-purpose music composition and editing environment.
the original thing about this one, is that it has musical notation, and you can load real audio just by droping it in the tracks, the bad thing is that it doesnt come with any sound, so via jack we have to load sounds from other synths...