I was living for a time in Nicaragua, decades ago, on a homestay type trip.

The family I was staying with once took me to a beautiful clear stream once, where people do laundry and also washed their hair.

The thing I will always remember is that - they had no shampoo, so they bought little one-time-use packets of shampoo from a roadside vendor, on the way up to the stream.

Buying it like that must have cost tons more than just buying a bottle of shampoo once.