The Land
While there are a few ‘important’ people in these villages who may own quite large 
stretches of land, and have a herd of cows as well as matoke plantations (green bananas) , the majority struggle from day to day to make ends meet.
They are likely to have an acre or so of land that was passed down from father to son, and getting smaller with each generation that passes. Their challenge is that although in places they have better medical facilities so fewer children are dying and the elderly are living longer, there has not been enough education with regards to limiting family size!
On their land they grow the bananas trees which are their staple diet, together with beans, ground nuts and some greens or cabbages. Millet is also grown and processed at home but the posho (maize meal) is generally purchased from a local supplier. Fruit is available cheaply when in season ( hence my request for funding for a solar drying system ) Meat, Fish, Rice and Spaghetti are all available but there are a rare treat for many.
Fruit Drying
Farmers tend to have all their crops ripen at the same time, thus causing the prices to drop, but they have no facilities such as freezers for keeping them. A few miles away there are a number of groups using fruit-drying cabinets and these fortunate growers have been trained to make and use these solar dryers by a company called ‘Fruits of the Nile’ This company has a contract to export dried fruit to UK, and are looking to expand their market.
Great, but it costs approx £1,000 to set the whole system up and train about 20 farmers in buying the materials and building the dryers, preparation of the fruit, hygiene, inspection and account keeping.
Mushroom Growing
It would cost about £1,500 to buy all the required materials and train a large group of villagers in all aspects of starting up, building, growing drying and marketing mushrooms. This can be a very lucrative long-term investment. A volunteer offering to fund this can themselves learn while actively helping organise the group.
Small Livestock Projects
Many different types of small animals can make a good regular income for a family unit, but they need seed capital to start them off. Rabbits, Goats, Ducks, Laying Hens, Broilers, Turkeys, Beekeeping, Pigs, Goats, and even a house cow can all be funded with a few hundred pounds capital for each project. 
Things to consider are cost of building the shelter (hive, hutch etc) cost of purchasing the animals and cost of their food until they start to show an income, as well training for those looking after the animals.