Solar stills....can be much cheaper.
You need:
Wet dirt or ground and/or water/urine/seawater/green vegetation.
A way to scoop a hole in the dirt.
A square meter or two of clear plastic.
A container, open topped.
Plastic tubing (optional)
Smallish rock. 200-300gms.
Scoop out hole maybe 30cm smaller in diameter than the plastic sheet.
Bury about half of the sheet's edge along the top of the hole.
dump water containing fluids/vegetation around the center of the hole, leaving room for you container.
Insert end of optional plastic tubing into pot, bring other end outside of the edge of the hole.
Bury the rest of the plastic sheet edging at the edge of the hole (rocks/pebbles/dirt)
Place rock on sheeting and it will move to center. Wait as container fills with water condensed off of the sheet.
Clear plastic sheeting is nearly ubiquitous around the world, make sure that the piece you choose is clean and was not used to wrap toxic materials.
Total cost: $0 + 1/2hr time assuming you have a container (plastic bottles are also ubiquitous around the world, but any clean container will work, so long as you have a large enough opening so the condensate falls into the container.
