Studio One FREE has a very similar layout to Cubasis so if you are used to Cubasis then I recommend this.
Reaper is a Free and easy to use DAW. It’s ease of use is what makes it so popular
MU LAB is another good free DAW especially for analogue type synth programming.
A very rare but FREE and useful DAW from Japan
If you are using the mac, Garage band is probably one of the best.