I’m intrigued by the possibility of a parabolic cooker/still. All you need is relatively stiff paper (almost cardboard stiff but not quite).
Cover with aluminum foil, shiny side up, and rill it into a cone shape. Cut a hole in the bottom and it will focus the sunlight.
Ever use a magnifying glass and shine the sun on an ant? Same deal here. Concentrates the sunlight possibly hundreds of times! DO NOT stick your hand in the opening!!
There are all kinds of approaches that are cost effective.
Solar still can be a rectangular box black on all sides but one of the big sides is glass or plastic; this side faces up towards the sun. It has to sit at an angle and have black cloth or something to have water seep slowly down the bottom of the inside of the box where the sun’s rays heat it. It runs down the inside of the glass/plastic after it condenses on it, collect it at the bottom.
I’m conservative, but I’m not “against” using solar, wind, etc., power. I’m simply “against” setting up financial scams and ripoffs where the particular usage of solar, etc. power makes no economic sense.
People who have zero enginneering or manufacturing experience often fall prey to scams based on “belief” in some junk science. One of the big areas that people with not much experience completely forget or have no concept of is maintenance. Such as the case with the aging windmills we have that are proving too expensive to maintain.