For anybody intrigued by this, the next step may be a Microbrute, bassStation, or maybe a MS20 mini, all for < US$500 street. Used microbrutes can be had close to $200.
Or go completely other way and get the most basic MIDI controller and play around with Pure Data, SuperCollider and other fun stuff. Not saying that would better, but might be more approachable by the HN crowd and probably cheaper too.