An example of using a $2 sound card to sync a Pocket Operator PO-12 to Ableton Live.
Ableton Live sends MIDI sync to a Max patch. The Max patch sends audio pulses to the Pocket Operator. Ableton Live and the Pocket Operator will play back in sync.
Download the Max patch here: http://milkcrate.com.au/_other/downloads/max_patches/Sync_PO.maxpat
Download Max here: https://cycling74.com/
The $2 sound card can be found here, with free shipping: http://www.dx.com/p/mini-usb-2-0-3d-sound-card-adapter-translucent-blue-434225
Open Ableton Live, go to Preferences. Click on the "Link MIDI" tab, and set the output of a virtual MIDI bus to Sync On. In the example below, the IAC Driver (Bus 1) virtual MIDI bus is used.
Open up the Max patch. Select the virtual MIDI bus from the menu.
Go to the options menu and select Audio Setup. Set the output device to the $2 USB audio device.
Connect the headphone output of the USB sound card to the external input
of the Pocket Operator. Set the Pocket Operator so SYN2 (Sync In /
Stereo Out). Set the Pocket Operator to play. Pressing play in Ableton Live should now synchronise both devices.