Wool Diaper Covers
Wool is what was was used for diapering before rubber and synthetic fabrics became readily available. It's breathable, waterproof (if treated properly), and natural.
How do I use a wool cover?
Wool covers are either used with fitted diapers or prefolds with a snappi, velcro fastener, or pins.
Why are they so expensive?
There are two types if wool covers, sewn (usually made from recycled sweaters or wool fabric) and knitted or crocheted (from yarn).
I see no reason for a sewn wool cover to be expensive. Especially if the materials are obtained from the local Salvation Army or Goodwill store. It's four seams and a little math.
Knitted and Crocheted covers on the other hand are harder to make. Suitable wool yarn is generally expensive. In addition, a large, felted wool cover can take days to complete. So, $50 doesn't sound unreasonable for one of these to me.