eBay

Video demo : https://www.youtube.com/watch?v=0IgDaudYPOg

Hard to find one in better condition, has been tested and woks. Can't guarantee everything is up to spec re the electronics though, given its age. You can refer to the YouTube link to see it in action.

It produces a tone if the VCA sustain is on and you can adjust the pitch with both VCO range and VCR range. The ribbon controller also works.

The PAiA Gnome is a small, portable analog synthesizer produced as a DIY kit by PAiA Electronics starting in the 1970s. It was designed as a low-cost, ribbon-controlled "micro-synthesizer" to introduce electronic music synthesis. The Gnome is famously played by touching a conductive strip with a stylus, controlling VCO, VCF, and VCA circuits

Origin: Created by John Simonton at PAiA Electronics; originally intended to make wind noises before evolving into a full micro-synth.
Components: Featured a Voltage Controlled Oscillator (VCO), Voltage Controlled Filter (VCF), Voltage Controlled Amplifier (VCA), and two Attack/Release (AR) envelope generators.
Control Mechanism: Played using a conductive vinyl strip (ribbon controller) rather than a traditional keyboard, making it affordable and portable.
Power & Sound: Battery-powered (typically two 9V batteries) and known for producing unique electronic noises and tones, according to a Reverb listing.
Legacy: Recognized as a "cult classic" in electronic music history due to its role in making synth design accessible.

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From the mfg.

While it started out as purely an electronic instrument to make wind sounds, the Gnome turned into one of the smallest, most portable analog synthesizers ever manufactured. [It was also battery-powered.]

'The Gnome started out as an instrument that wasn't going to do anything more than making the sound of wind - not like a flute, but real wind. Ssssshhhhew. That kind of wind, which could be played with a little vinyl controller strip that was part of it.

The Gnome was one of those things that just grew. After the instrument that did the wind sound was done, it became pretty apparent that you could stick other components in there and essentially come up with a small synthesizer, a thing that captured the central ideas of voltage-controlled synthesis at the time - Oscillators, filters, transient generators, and so on - but stripped down to the essentials or the core. It was an attempt to get rid of that keyboard that was always by far the single most expensive part of anything we made, by order of magnitude or more.