Right out of college I moved to Guatemala to work for a social enterprise. We worked mostly with women within a consignment model. We'd loan a woman a supply of reading glasses to sell, and once she sold them, she'd pay us back what the glasses cost. Since she didn't need capital up front, she could start a business and provide a service her town didn't have, without needing money she didn't have.
The way we sold them was through what we called a vision campaign. We'd visit a town a week ahead of time, sit down with the mayor, get permission to use a central building, spend a few dollars on radio announcements, hang some flyers, and come back the following week ready to sell. This was almost twenty years ago, and reading glasses weren't something you could buy in a small town. If your close-up vision was going, fixing it meant knowing a solution existed, then taking a day off work and a bus to a bigger town to buy glasses. Plenty of people never made that trip, either because they didn't know this product existed or couldn't spare the time and money, and so they lost the ability to weave, read, and do the detailed work their livelihood depended on.
One Saturday morning I went out to a campaign with three women, and it was a smashing success. We arrived and the line was already wrapped around the community building. The women performed basic vision exams and sold glasses all day without stopping. By the time we packed up, each woman had made over a hundred dollars, a significant amount of money for a day's work.
I said goodbye and told them to call me the next week so we could start planning the campaigns for neighboring towns.
I didn't hear from them for a month, maybe longer.