I was looking at some of the life raft accessories and I came across some inflatable solar stills. I realize these are a very slow way to make water ready to drink, but I thought they might be useful and they fold down pretty compact when deflated.

Whenever I see sources for them we're talking ~$200 or more! They have a simple design and look like they cost almost nothing to produce... Is there a reason they are so expensive, and is there a cheaper alternative out there?

if you are a DIY person, an idea that showed promise for a small scale plant you can make multiples of... a couple of years ago I played around with some solar desal ideas... I wanted to utilize a wicking function to increase the surface area... the problems centered around the difficulty of draining small amounts of condensate off the glazing material...at first I tried a water lens to increase temp, but a practical solution was more expensive than I wanted... by my third attempt, I had produced something similar to the picture....a translucent leaf bag as glazing, collector panel, and storage container...the pic is a preliminary trial, but unfortunately I can't find pics of the final version..., the final version was free hanging....used a small plastic dish pan with a standoff ring of aluminum clothes line slightly outboard, and tripod hanging support... the dish pan had an inverted plastic container over which a black cotton towel for a collector surface was laid (the fabric would wick the brackish water up and expose it to more surface area... to hold the bag in shape, a golf ball was placed in each edge corner, and condensate collects there.. you need a pretty steep side...you get quite a bit of condensation at night, so over a 24hr test cycle, I was obtaining about 250ml of condensate... this pic shows a center tube of 1/4" hardware cloth support for the black wicking cloth

for commercial applications you might look at "water pyramids"

I filed this away under useful knowledge for salt water desal.. there is too much of a chance for contamination for raw water

Interesting thanks!