Click here to Buy it Now from the Apple App Store, $33

Yes, this is the most expensive app on this list, but that's because you get a faithful reproduction of one of the illest production machines ever made: the Korg MS-20 analog synth. The app features MS-20 synth along with a 16-step analog sequencer modeled after Korg's SQ-10, a six-pad drum machine, a seven-channel mixer, and 14 effects. But we're sure you'll have more fun creating your own sounds. Once you're done you can export your creations to SoundCloud. Go nuts.