The CymaScope is a purpose-built device that imprints sound onto a shallow, circular water membrane and photographs the resulting surface. Its own site describes it as "the first scientific instrument that can provide an analog image of sound and vibration". Most of the polished cymatic stills circulating online originate either from this device or from imitations of its look.
It is worth being clear-eyed about the framing. The site lists application areas including asteroseismology, biology, botany, musicology, neurophysiology, oceanography, physics, sound therapy and zoology. Some of those are ordinary acoustics; "sound therapy" is not an established clinical field, and nothing on the page constitutes evidence that visualised sound treats disease. Read the instrument as an imaging rig with a distinctive optical design, not as a diagnostic tool.
No prices are stated on the main site; purchasing runs through a separate shop.