Mix'n Match audio files

[Ghost Snake]

So I've got a bunch of music sections exported to mp3. Since they aren't finished tracks, I would really like to experiment with them, for instance using one as a verse, the other one as a chorus. I need something that will set the audio events to a specific time, and with good real time pitch shifting. Acid comes to mind, but is it discontinued ? I use reaper but it's so complex I get a headache, and Cubase audio warp function sounds grainy.

Any free software ? I remember Recycle doing something similar, but for the transients.....