How much do the SOTA units cost? (as of Sep. 2019)
Several online sources offer SOTA products, usually at the same price as SOTA (located in Canada).
Without affiliation, the following site is run by Volker Risto, who worked with Dr. Bob Beck from 1985 to 2003. Unlike SOTA (who are legally restricted by Health Canada), he is able to offer detailed information on products by telephone. He also has a 2 day delivery time by priority mail from California, and is able to ship internationally at a lower cost than SOTA.
And by the way - you can usually find used
units on ebay.