It's $450 US + shipping.

You get ene Ekdahl Quad Massager and one american power supply (optional)

Yes, it's US$90 (non-refundable, deducted from the total price) to buy parts and secure the purchase

There are two versions of the Ekdahl Quad Massager, the old version (R1) takes a 12V AC OUT supply at 500mA or more. These are getting hard to come by but you should still be able to find one online. Please note that things that are just called "an AC supply" may not actually be an AC/AC supply but sometimes just means that it takes AC IN - the Ekdahl Quad Massager doesn't care what comes into the power supply but just what comes out of it and you need AC OUT - NOT DC!

The new version of the Ekdahl Quad Massager (R2) on the other hand takes a 15V - 20V DC @ minimum 500mA - any polarity - which is easy to find.

Both supplies use a standard 2.1mm barrel connector

The unit should work with anything within the normal 0-10V range of CV, in fact, it should probably be able to withstand up to 20V but I DO NOT GUARANTEE IT OR TAKE ANY RESPONSIBILITY.