Roland TB-303 for sale. Fully serviced and in perfect working order, unlike most. All switches replaced, so no annoying retriggering. A previous owner added a multipin connector to the left side of this one, apparently for use with an MSQ-700 sequencer, but we saw little use for this modification and had no way to test it, so we removed its wiring during its restoration. The port remains, but it's completely nonfunctional. You could of course use it to expand this 303s function, if you or someone you know is good at DIY electronics.
The computer-controlled bassline helped create acid house music back in the late 80s when people couldn't give them away. The internal sequencer can be used to play other compatible CV gate instruments and works quite well with other roland music machines in the x0x box family.