LMMS

I love this daw. This is what i used before i upgraded to FL studio. If you dont have the money to afford one of the more well known professional daws like fl studio, ableton, logic pro, or protools, LMMS is awesome for a free daw. There are no limitations really. It has a step sequencer, piano roll, linear playlist, comes bundled with internal plugins like synths and drum makers, mixing and mastering tools, mixer with routing capbilities and an infinite fx chain, and it is compatible with a lot of vst's. The only thing this program lacks are some of the advanced features of programs like fl studio and ableton, but a lot of those things can still be accomplished manually. It also has automation. Very good daw for free.